I have a few email accounts over at Yahoo called throwaway email accounts that I use when I am posting in online forums for example. When these accounts start getting spammed out I close the account. Easy. And all this helps keep my life-long email addresses relatively spam free.
The problem is I have to sign in and sign out to read each accounts contents. Microsoft has recognized the need for throwaways, especially in pro-sumer and technical user areas, and created a single login system for multiple throwaway email addresses.
You can find out more over at cnet.