[metaxy2]

I remember it taking a few years between DHTML becoming a buzzword and XHR becoming popular. XHR was slept on for a while even though it was available in all major browsers by the early 2000's. Back when we were calling things "DHTML," updates originating from the server typically would happen by refreshing the whole page, or sometimes an IFRAME if you wanted to get fancy [1]. Once XHR finally started to get popular is when people started talking about "Web 2.0" in the mid 2000s.

I heard that someone did a talk on why it took so long for the Web 2.0 phenomenon to happen even though the technologies were available for several years before. Can't remember who.

A little known fact is that even streaming updates (e.g. for live chat) were actually not that hard to implement on the front end going back to the original days of XHR, via "long polling" (basically starting a new XHR request that you held open until the next piece of info comes in) though it took until well into the Web 2.0 era for that to be common. The problem was actually on the server side; to cope with long polling, the server would have to keep a long-running thread (and in the case of CGI, a whole process!) for each of those open requests and the servers would get overloaded. Nowadays of course servers have much better hardware, and we have technologies like nginx that can handle huge amounts of connections in one thread.

In principle you could build almost everything in the modern day front page of Facebook or Google results page with the tools we had in 2001, front-end wise, but the servers couldn't handle long polling for the streaming updated needed for things like the Facebook chat. Also the pages are so complex that it would be easy to get yourself tied in knots without modern conveniences like CSS frameworks (or even resets!)

[1] https://en.wikipedia.org/wiki/Dynamic_HTML