log in to a website with more than user name at once

[plg6067]

I stumbled upon this because I needed it for non-ebay/paypal-related reasons and I am guessing some of you may find it helpful. It lets you choose cookie profiles (at least in the thing for firefox,I didn't read the thing for ie)

he is where I found it link
sorry if this a repeat post, I didn't see any similar ones but maybe I am blind