Here's another site that serves your need for a temporary email address. The address is assigned to you and then expires in ten minutes. If you need longer, just extend your time when you get your address. Useful if you need to sign in to read a site, but don't want to mess around with unsubscribing when you are done.
Implications - This is also a nifty way around having to deal with pesky e-mail newsletters that get sent to you whenever you register with a new website. Instead of giving away your actual information, you could easily create a temporary address in its place. Now you can sign up for any site without clogging your inbox.