MySpace, Microsoft.com, Asp.Net
Are all examples of large sites written in asp.net
Asp.Net has a page lifecycle with postback, events, viewstate and sessionstate. These things are not part of http and in most platforms have to be done semi-manually. Asp.net developers are spoiled in this way and don't always have a complete grasp on the complexities of the http protocol. there is nothing wrong with this and there are plenty of large sites in asp.net.
If you want to use Asp.net and get to know http you can try the MVC approach which gets rid of postbacks, viewstate and the event model but still lets you take advantage of the ease of programming in .Net