I have been doing some reading up on Facebook's announcement that it has been developing a new web server, specifically for PHP apps. Apparently it will convert PHP code into C++ for more efficient running.
Facebook say they have been using HipHop for a little while and it is a lot more efficient than Apache. Apparently now over 90% of their pages are served using it.
I can't wait for an official release, I may setup a VM just to try it out. It would be nice to have a dedicated PHP web server, rather than just piggybacking off more generic ones (not that I am slating Apache though, its a pretty fine server).
The official Facebook announcement, and details, can be found here: http://developers.facebook.com/news.php?blog=1&story=358