One things that’s a bummer. Some of us keep two accounts in one e-mail provider. Like for example, some would have two or more Gmail accounts. However, more often than not, you can only open one account at a time in a browser.
One quick way around this is to have two browsers open (usually IE and Firefox). But as we have experienced, we hate switching multiple from one window to the next (hence our love for tabbed browsing). Good thing there’s an add-on for Firefox that allows you to have an Internet Explorer tab run inside Firefox. So you can now sign-in into two Gmail accounts at the same time. It’s called IE Tab.
Just download the add-on. Pop up a new tab, switch it to an IE rendering engine and voila! You got one Firefox tab for one account and and IE tab in Firefox for another. Neat huh?