They usually involve generics. But some methods with generics don't have them, and not all extension methods have them. They've just "been there" since day one, we've all seen them; but I realized I still don't know what they mean, and I can't find the answer anywhere. Now it's really bugging me. Google just turns up results that are about XML, etc. Is this officially documented anywhere? Thanks. EDIT: Well that's just great. Since I just created an account to make my first Stack Overflow post, to get an answer for this burning question; I'm not allowed to post my pretty Intellisense picture, or create a new tag "angle-brackets". I love Stack Overflow, but... what a welcome! Maybe my problem is that they aren't actually called "angle brackets"... ?? Anyway, I guess if you really want to see my beautiful screenshot you could manually go to: http://www.freeimagehosting.net/uploads/6a6c2f3268.png Bump me up please so I can include it in the post, thanks. ;)