I may be unusual but those sites both work great on my 7 year old Macbook Pro running Google Chrome on a 5O Mbs internet connection. Which brings up the point

I may be unusual but those sites both work great on my 7 year old Macbook Pro running Google Chrome on a 5O Mbs internet connection. Which brings up the point someone brought up is that the developers, QA testers, and managers at those companies probably have more modern computers and even faster network. But there are some ways around that like VMs and virtual network interfaces that intentionally throttle the speed and performance and I would be surprised (although not TOO surprised) if no one on the QA teams at those companies used them. Another thing as others pointed out is that these apps are insanely complicated. They have live updating, undo, advertising, inline preview of links, search, autocomplete, etc... tons of features that many users will never use. And that's just the client-side complexity. Part of that is due to user demand and part of it is due to the app just slowly getting more complicated over time (call it feature creep and technical debt). And part of that may also be because as one cynical (albeit probably not wrong) person put it, there are huge teams working on many of these features[1] that need to justify their budget by showing "results." You may also be assuming that 1000 features that are easy to build, maintain, and keep bug free scales to a single system that is easy to do those things. It rarely works that way because components need to interact with each other and by necessity you have multiple people (multiple teams in fact) who need to integrate their stuff together. [1] Some of the features I'm sure have more team members than my entire startup company just to build one feature.