I'm very disappointed to learn that both WordPress.org and WordPress.com are using LiteSpeed, a COMMERCIAL alternative to Apache.
Choosing to go with a very expensive commercial product (it costs $250 per CORE, so for instance a license for a dual Opteron 280 would run you $1,000) instead of supporting LightTPD ("Lighty") or NGINX means losing a golden opportunity to advance these excellent Apache alternatives.
WordPress is a model project on the power of open source, and it has enough muscle to speed up the development of more efficient webserver alternatives such as those mentioned.
I wonder if they are paying the very expensive LiteSpeed licenses for all the servers that run WordPress.org and WordPress.com, but I wouldn't be surprised if it's the other way around, LiteSpeed paying them to promote their product mentioning WordPress. In either case, it's a wasted opportunity.
And BTW, if anybody knows how to run WordPress with Lighty or NGINX, please post a tutorial somewhere, I failed miserably trying to set up WordPress with Lighty even though I read everything I could find.