"How web bloat impacts users with slow devices"
Dan Luu benchmarked a bunch of different web platforms to illustrate the bloat that makes some of them completely unusable on lower-end mobile devices. His analysis was incredibly illuminating, and I thought his comments on CPU vs. bandwidth were interesting:
It's still the case that many users don't have broadband speeds, both inside and outside of the U.S. and that much of the modern web isn't usable for people with slow internet, but the exponential increase in bandwidth (Nielsen suggests this is 50% per year for high-end connections) has outpaced web bloat for typical sites, making this less of a problem than it was in 2017, although it's still a serious problem for people with poor connections.
CPU performance for web apps hasn't scaled nearly as quickly as bandwidth so, while more of the web is becoming accessible to people with low-end connections, more of the web is becoming inaccessible to people with low-end devices even if they have high-end connections.
I also liked his callout on LCP, which fits well with some of my recent complaining about web animations:
As sites have optimized for LCP, it's not uncommon to have a large paint (update) that's completely useless to the user, with the actual content of the page appearing well after the LCP. In cases where that happens, I've used the timestamp when useful content appears, not the LCP as defined by when a large but useless update occurs.
He rightfully points out some of the issues with "Core Web Vitals", such as its omission of CPU time: "if a page has great numbers for all other metrics but uses a ton of CPU time, the page is not going to be usable on a slow device". Perhaps it ought to be added, given that it is considerably more challenging to teach to the test when it comes to CPU — that is, optimize for the metrics rather than make meaningful improvements to the end user experience.
This is also incredible:
While reviews note that you can run PUBG and other 3D games with decent performance on a Tecno Spark 8C, this doesn't mean that the device is fast enough to read posts on modern text-centric social media platforms or modern text-centric web forums. While 40fps is achievable in PUBG, we can easily see less than 0.4fps when scrolling on these sites.
I liked his notes about how attempts to optimize for slow devices through lazy-loading are often counterproductive:
Sites that use modern techniques like partially loading the page and then dynamically loading the rest of it, such as Discourse, Reddit, and Substack, tend to be less usable than the scores in the table indicate. Although, in principle, you could build such a site in a simple way that works well with cheap devices but, in practice sites that use dynamic loading tend to be complex enough that the sites are extremely janky on low-end devices. It's generally difficult or impossible to scroll a predictable distance, which means that users will sometimes accidentally trigger more loading by scrolling too far, causing the page to lock up. Many pages actually remove the parts of the page you scrolled past as you scroll; all such pages are essentially unusable. Other basic web features, like page search, also generally stop working. Pages with this kind of dynamic loading can't rely on the simple and fast ctrl/command+F search and have to build their own search.
Some other excellent points:
There are two attitudes on display here which I see in a lot of software folks. First, that CPU speed is infinite and one shouldn't worry about CPU optimization. And second, that gigantic speedups from hardware should be expected and the only reason hardware engineers wouldn't achieve them is due to spectacular incompetence, so the slow software should be blamed on hardware engineers, not software engineers. ...
Another common attitude on display above is the idea that users who aren't wealthy don't matter. When asked if 100% of users are on iOS, the founder of Discourse says "The influential users who spend money tend to be, I’ll tell you that".