To me, it coincided with async (long polling/comet/SSE), more live, web applications. Apache had a horrible story around this, with one thread per connection (I believe Apache 2 may have had an optional execution model, which was also uncomfortable for some reason).

I used lighttpd for this, mentioned in another thread, rather than nginx, which was a similar breath of fresh air coming from Apache -- not only for the event loop model built around epoll and friends, but also the configuration and general deployment.