Yes, that's right. You can add your own custom functionality to the My namespace. Microsoft has even created a My.Blogs library that adds functionality for read and writing to blogs. And, there is an MSDN TV episode that explains how to use My.Blogs.
Simplify Common Tasks by Customizing the My Namespace
My.Blogs Code Sample for Visual Basic
MSDN TV: Adding Blogging to Your Apps with My.Blogs and Visual Basic 2005