Lots of people make multiple accounts on websites for everything from roleplaying to … well, I don’t know what else you’d do it for. And then it’s annoying, because you have to log in and log out, or use six different browsers, and IE is ugly, and Firefox eats memory, and Chrome is nasty to linux (sometimes).
This is how you fix that.
IE doesn’t do addons, but it does sessions, something sniped from php and put to use by Mircrosoft. You can use that in ver. 8+ to switch between accounts on the same browser.
Firefox has the handy Cookie Swap plugin, which allows you to switch between sets of cookies and therefore logins.
Chrome has two options: Cookie Switcher and Swap my Cookies (which I use).
A search for a similar add on for Opera and Safari turned up nothing, though as both browsers use addons I’m sure something will be forthcoming soon.
Multi-account roleplaying, or login, made easy.