Dan Luu
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Dan Luu
@danluu.com
3.2K followers 13 following 41 posts
Active on Mastodon: https://mastodon.social/@danluu. Also trying https://threads.net/@danluu.danluu
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Interesting story about Google publishing someone's phone number on searches when they gave the number to Google for account verification/security:

danq.me/2025/05/21/g...

Reminds me of the time a company I worked for accidentally used phone numbers obtained the same way and got fined $150M
After the first three such calls this month, I was really starting to wonder what had changed. Had we accidentally published my phone number, somewhere? So when the fourth tech support call came through, today (which began with a confusing exchange when I didn’t recognise the name of the caller’s charity, and he didn’t get my name right, and I initially figured it must be a wrong number), I had to ask: where did you find this number? “When I Google ‘Three Rings login’, it’s right there!” he said.
May 26, 2025 at 7:15 AM
A version of Missile Command for the Commodore 64 where the bottom of your screen is the game state in memory and missiles cause memory corruption: csdb.dk/release/?id=....

In the video below, a missile broke my controls and caused my cursor to get stuck moving down and to the left.
November 22, 2024 at 10:56 PM
The commentary I've seen says Teslas are safe so it must be the drivers but, per danluu.com/car-safety/, maybe it's the cars. The most fatal rated manufacturers (Kia/Hyundai, Dodge, Tesla) all did poorly — Kia/Hyundai, Dodge got the lowest rating and there's a strong case Tesla should have as well.
The ranking below is mainly based on how well vehicles scored when the driver-side small overlap test was added in 2012 and how well models scored when they were modified to improve test results. Tier 1: good without modifications Volvo Tier 2: mediocre without modifications; good with modifications None Tier 3: poor without modifications; good with modifications Mercedes BMW Tier 4: poor without modifications; mediocre with modifications Honda Toyota Subaru Chevrolet Tesla Ford Tier 5: poor with modifications or modifications not made Hyundai Dodge Nissan Jeep Volkswagen These descriptions are approximations. Honda, Ford, and Tesla are the poorest fits for these descriptions, with Ford arguably being halfway in between Tier 4 and Tier 5 but also arguably being better than Tier 4 and not fitting into the classification and Honda and Tesla not really properly fitting into any category (with their category being the closest fit), but some others are also imperfect. Details below.
November 17, 2024 at 8:29 PM
I find it interesting/surprising that Tesla topped the www.iseecars.com/most-dangero... fatalities per mile ranking from 2018-2022.

Fatality rate is strongly negatively correlated with price and weight and Teslas are much more expensive and heavier than average.
Please see link for text version of table Please see link for text version of table Bar chart showing that Teslas have a higher average selling price than any other tracked car manufacturer
November 17, 2024 at 8:29 PM
Steve Ballmer was an underrated CEO

danluu.com/ballmer/
There's a common narrative that Microsoft was moribund under Steve Ballmer and then later saved by the miraculous leadership of Satya Nadella. This is the dominant narrative in every online discussion about the topic I've seen and it's a commonly expressed belief "in real life" as well. While I don't have anything negative to say about Nadella's leadership in this post, this narrative underrates Ballmer's role in Microsoft's success. Not only did Microsoft's financials, revenue and profit, look great under Ballmer, Microsoft under Ballmer made deep, long-term bets that set up Microsoft for success in the decades after his reign. At the time, the bets were widely panned, indicating that they weren't necessarily obvious, but we can see in retrospect that the company made very strong bets despite the criticism at the time. In addition to overseeing deep investments in areas that people would later credit Nadella for, Ballmer set Nadella up for success by clearing out political barriers for any successor. Much like Gary Bernhardt's talk, which was panned because he made the problem statement and solution so obvious that people didn't realize they'd learned something non-trivial, Ballmer set up Microsoft for future success so effectively that it's easy to criticize him for being a bum because his successor is so successful. Criticisms of Ballmer For people who weren't around before the turn of the century, in the 90s, Microsoft used to be considered the biggest, baddest, company in town. But it wasn't long before people's opinions on Microsoft changed — by 2007, many people thought of Microsoft as the next IBM and Paul Graham wrote Microsoft is Dead, in which he noted that Microsoft being considered effective was ancient history: A few days ago I suddenly realized Microsoft was dead. I was talking to a young startup founder about how Google was different from Yahoo. I said that Yahoo had been warped from the start by their fear of Microsoft. That was why they'd po…
November 17, 2024 at 8:32 PM
A former Apple engineer discusses Google product culture:

> My director wore an Apple Watch and had an iPhone ... my VP too. Nobody was expected to eat the dog food and so few did. This was crazy to me coming from Apple ....
mattnewton 1 hour ago | parent | next [–] When I worked at Google I got re-orged into the same division as pixel / android. My director wore an Apple Watch and had an iPhone for personal use, and I am pretty sure I saw an Apple Watch on my VP too. Nobody was expected to eat the dog food and so few did. This was crazy to me coming from Apple- I remember several internal sites would ask you to file a radar (bug report) on why you switched to chrome from safari if you opened them in chrome. So many crazy issues I saw and reported didn’t actually matter to many high ranking members of the pixel team because they didn’t use the devices after 5pm. There is a lot of incredible talent in that team but I think Google needs a minor culture shift to compete with Apple here.
November 17, 2024 at 8:32 PM
On the 2011-2012 FTC antitrust investigation of Google:

danluu.com/ftc-google-a...
This is a summary of the publicly available documents on the 2011-2012 FTC investigation of Google's allegedly antitcompetive actions in search and ads, followed by a tech-focused analysis of the decision from someone who's worked at the two companies that are discussed in the most detail in the memos (Google and Microsoft), worked in search, and worked closely with ads teams on optimizing ads ranking algorithms. I've seen a number of law-focused and economics-focused analyses, but I haven't seen a tech-focused analysis in a level of detail I find satisfying. In particular, a number of key arguments in the memos rely on evidence and inferences that would've seen implausible to someone who was familiar with tech, which I haven't seen discussed. The law-focused and economics-focused analyses tend to avoid digging into this and, while there have been some articles written about tech errors for a lay audience, they've tended to explain that the inferences that were made were wrong in r...
November 17, 2024 at 8:32 PM
Every once in a while, I think about going to work in the game industry.
@ZTGallagher • 1mo ago I know a guy who was a QA tester for Obsidian Entertainment working on Neverwinter Nights 2. At the end of development, they invited all the QA testers to the parking lot for a celebration party. There was no party, they disabled all their keys when they got out there, and told them they were all fired. And that was it...
November 17, 2024 at 8:32 PM
Interesting comment about SGI leadership knowing about the problems they were facing and still being unable to come up with a way to handle them.
November 17, 2024 at 8:32 PM
How web bloat impacts users with slow devices:

danluu.com/slow-device/
Table showing that many websites are unusable with devices that are commonly used in non-rich countries. See link for details.
November 17, 2024 at 8:32 PM
We're coming up on a decade since danluu.com/cpu-bugs/. Not only was the prediction valid for a decade, it looks like the next decade will be worse.

Today's bug of the day: a significant fraction of high-end consumer CPUs crash if you run CPU-intensive workloads: www.radgametools.com/oodleintel.htm
Intel Processor Instability Causing Oodle Decompression Failures RAD has become aware of a problem that can cause Oodle Data decompression failures, or crashes in games built with Unreal. We believe that this is a hardware problem which affects primarily Intel 13900K and 14900K processors, less likely 13700, 14700 and other related processors as well. Only a small fraction of those processors will exhibit this behavior. The problem seems to be caused by a combination of BIOS settings and the high clock rates and power usage of these processors, leading to system instability and unpredictable behavior under heavy load. As far as we can tell, there is not any software bug in Oodle or Unreal that is causing this. Due to what seem to be overly optimistic BIOS settings, some small percentage of processors go out of their functional range of clock rate and power draw under high load, and execute instructions incorrectly. This is being seen disproportionately in Oodle Data decompressi...
November 17, 2024 at 8:32 PM
Diseconomies of scale in fraud, spam, support, and moderation:

danluu.com/diseconomies...
f I ask myself a question like "I'd like to buy an SD card; who do I trust to sell me a real SD card and not some fake, Amazon or my local Best Buy?", of course the answer is that I trust my local Best Buy1 more than Amazon, which is notorious for selling counterfeit SD cards. And if I ask who do I trust more, my local reputable electronics shop (Memory Express, B&H Photo, etc.), I trust my local reputable electronics shop more. Not only are they less likely to sell me a counterfeit than Best Buy, in the event that they do sell me a counterfeit, the service is likely to be better. Similarly, let's say I ask myself a question like, "on which platform do I get a higher rate of scams, spam, fraudulent content, etc., [smaller platform] or [larger platform]"? Generally the answer is [larger platform]. Of course, there are more total small platforms out there and they're higher variance, so I could deliberately use a smaller platform that's worse, but I'm choosing good options instead of...
November 17, 2024 at 8:32 PM
Why it's impossible to agree on what's allowed:

danluu.com/impossible-a...
Plot showing that almost everybody disagrees with almost everybody else on a simple question (see link for further explanation).
November 17, 2024 at 8:32 PM
Notes on the accident where a Cruise self-driving car dragged a pedestrian under the vehicle for 20 feet after hitting them:

danluu.com/cruise-report/
Alt text too long for field. Please see link.
November 17, 2024 at 8:32 PM
Why do people post on [bad platform] instead of [good platform]?

danluu.com/why-video/
There's a class of comment you often see when someone makes a popular thread on Mastodon/Twitter/Threads/etc., that you also see on videos that's basically "Why would make a Twitter thread? This would be better as a blog post" or "Why make a video? This would be better as a blog post". But, these comments are often stronger in form, such as: I can't read those tweets that span pages because the users puts 5 words in each reply. I find common internet completely stupid: Twitter, tiktok, Instagram, etc. What a huge waste of energy. or When someone chooses to blog on twitter you know it's facile at best, and more likely simply stupid (as in this case) These kinds of comments are fairly common, e.g., I pulled up Foone's last 10 Twitter threads that scored 200 points or more on HN and 9 out of 10 had comments like this, complaining about the use of Twitter. People often express bafflement that anyone could have a reason for using [bad platform], such as in "how many tweets a...
November 17, 2024 at 8:32 PM
How bad are search results and how do small, independent, search engines compare to Google and Bing?

danluu.com/seo-spam/
Table of search result quality on test queries. From best to worst, we have Marginalia, ChatGPT, Mwmbl, Kagi, Google, and then Bing.
November 17, 2024 at 8:32 PM
automotive engineers had to fight designers to get headlights that illuminated the road. They were losing until Consumer Reports started testing headlights for function, which created enough bad PR that engineers were able to push for headlights that actually work: danluu.com/why-benchmark/
Vehicle headlights: Jennifer Stockburger has noted that, when Consumer Reports started testing headlights, engineers at auto manufacturers thanked CR for giving them the ammunition they needed to force their employers to let them to engineer better headlights; previously, they would often lose the argument to designers who wanted nicer looking but less effective headlights since making cars safer by desiging better headlights is a hard sell because there's no business case, but making cars score higher on Consumer Reports reviews is an easy sell because that impacts sales numbers
November 17, 2024 at 8:32 PM
"The algorithm" has somehow decided that I want to see viral UX/designer content.

In every viral UX comparison I've seen so far, the "good" version looks more modern but is also less legible / usable. E.g., below, the contrast is lower and legibility is sacrificed for to make things look clean.
Comparison where "good" version is low contrast and critical information is hard to read. Comparison where "good" version is low contrast and critical information is hard to read.
November 17, 2024 at 8:32 PM
Looking back on this 2015 post about how AI will displace humans, I feel like I got the line of reasoning correct, in that the same debate is happening today and this post pre-emptively refuted the incorrect reasons people are now giving for why LLMs aren't a big deal:

danluu.com/customer-ser...
There's an ongoing debate over whether "AI" will ever be good enough to displace humans and, if so, when it will happen. In this debate, the optimists tend to focus on how much AI is improving and the pessimists point to all the ways AI isn't as good as an ideal human being. I think this misses one very important factor, which is that the most obvious jobs that are on the potential chopping block, such as first-line customer service, customer service for industries that are either low margin or don't care about the customer, etc., tend to be filled by apathetic humans in a poorly designed system, and humans aren't even very good at simple tasks they care a lot about. When we're apathetic, we're absolutely terrible; it's not going to take a nearly-omniscient sci-fi level AI to displace people in most customer service jobs. For example, here's a not-too-atypical customer service interaction I had last week with a human who was significantly worse than a mediocre AI. I scheduled an ap...
November 17, 2024 at 8:32 PM
The difference in the "What's Hot" feed on Bluesky right now vs. Mastodon really sums up why I've found it so much easier to find discussions I like on Mastodon.

Bluesky is full of people crowing over their superiority over threads users. Mastodon has less Threads content but, more importantly
Bluesy What's Hot fishttp:// · 23h @fish.posting.lol Follow Every screenshot of Threads I've seen is basically 𝐇𝐞𝐢𝐧𝐳 who getting they ketch upped?? 8,729 𝘳𝘦𝘱𝘭𝘪𝘦𝘴 · 𝘭𝘪𝘬𝘦𝘥 𝘣𝘺 𝘞𝘦𝘭𝘭𝘴 𝘍𝘢𝘳𝘨𝘰 𝘢𝘯𝘥 𝘉𝘪𝘭𝘭 𝘊𝘰𝘴𝘣𝘺 Katie Mack · 19h @astrokatie.com Follow Whatever the opposite of FOMO is, I feel that about Threads John Scalzi · 1d @scalzi.com Follow On Twitter in one of my threads someone just said "Threads had 30M signups in one day, Bluesky has lost its chance to become the next Twitter" and he may be right, but what he doesn't know is that people here are like "cool, dodged THAT bullet" Zack Budryk · 23h @zackbudryk.bsky.social Follow Threads stole Elon Musk’s idea, a social media platform that sucks Lindsay Fickas · 1d @lindsayfickas.bsky.social Follow Threads: we’re going to scold you for using the word “fuck” Bluesky: please make sure that picture of your ass has alt text so everyone can enjoy it 💕💕 Ed Yong · ... #Explore 7h crowgirl@hachyderm.io Kim Crawley @crowgirl@hachyderm.io This is a warning about Meta and Threads. Please boost this here and outside of Mastodon so that pregnant people in the United States are informed that using Meta/Threads is dangerous. I'm unlikely to get pregnant but I have ZERO presence on Meta/Facebook/Instagram/Threads as a matter of principle. #abortionrights #pregnant #threads 5h protonmail Proton Mail @protonmail So #Meta's new #Threads app needs your health and fitness info. It also needs your browsing history and your location, and your purchases, and...well, it seems to need everything. If you want to get fully creeped out, here's the whole #privacy policy: https://privacycenter.instagram.com/policy/.
November 17, 2024 at 8:32 PM
how it started how it's going
@unusual_whales Nov 15, 2022 Elon has fired numerous employees who were critical of him on Twitter and the company’s Slack, according to Protocal. @elonmusk I would like to apologize for firing these geniuses. Their immense talent will no doubt be of great use elsewhere. 17.7K Retweets 3,832 Quotes 276.1K Likes 1,048 Bookmarks @ajtourville Nov 15, 2022 These geniuses somehow managed to escape the 1st round of layoffs — Let that sink in! @elonmusk Nov 15, 2022 Seriously Dear Mr. Zuckerberg: I write on behalf of X Corp., as successor in interest to Twitter, Inc. ("Twitter"). Based on recent reports regarding your recently launched "Threads" app, Twitter has serious concerns that Meta Platforms ("Meta") has engaged in systematic, willful, and unlawful misappropriation of Twitter's trade secrets and other intellectual property. Over the past year, Meta has hired dozens of former Twitter employees. Twitter knows that these employees previously worked at Twitter; that these employees had and continue to have access to Twitter’s trade secrets and other highly confidential information; that these employees owe ongoing obligations to Twitter; and that many of these employees have improperly retained Twitter documents and electronic devices. With that knowledge, Meta deliberately assigned these employees to develop, in a matter of months, Meta’s copycat “Threads” app with the specific intent that they use Twitter’s trade secrets and other intellectual pro...
November 17, 2024 at 8:32 PM