I’m listening to the Hanselminutes Podcast; \"StackOverflow uses ASP.NET MVC - Jeff Atwood and his technical team\". During the course of the Podcast they are speaking about SQL
Judging from the lackluster performance of this site, I'm going to wager the major bottleneck is the database.
I'm not convinced in any way that the LINQ 2 SQL ORM they are using is one bit faster than a sproc.