A lot more in that post.
Facebook is great and all, but fuck it, it’s a walled garden. Twitter too, mostly. The fight for an open social web is on, with a combination of geeky protocols like OExchange for sharing urls, ActivityStreams for sharing activity streams (it’s an extension on Atom), OAuth and OpenID, microformats and many more. The infrastructure is being built and adopted by smart people in large companies (Google, …). It’s time for some awesome user experiences to be built on top of that. The current user experience of these open formats is still slightly dodgy compared to the closed alternatives, but they’re getting there. The same fight is being fought on mobile, with Android versus iPhone, although that’s somewhat of a mis-characterization since the iPhone has awesome html5 support and has pushed it hard.
At (Twitter) scale, it becomes hard to generate unique ID’s and sort with them, so they use something called k-sorts that aims at sorting things roughly, within a second of the time they were posted. Scale is weird, it’s like inverted quantum mechanics. You always seem to have to loosen things up a little to scale up. Even laws of nature seem to loosen up once you get away from our scale.