This one is a huge time saver - if you have two email accounts, and would like to be able to see your inbox on both, without needing to log out from one, to log in to another.
I said two accounts, but no it’s not limited to two accounts only. You can open as many accounts as you want, on the same site, all at once.
The same applies to all membership websites. You can access multiple accounts at the same time, on Facebook, Twitter, MySpace, Hotmail… whatever.
I bet you knew how to do this by using different browsers (Firefox, Chrome, IE…), and keeping them running all at once. But that just eats up your RAM memory, and makes your desktop look clogged. So no, we’re not going to use that method.