Now you can have multiple Gmail accounts open at once

If you’ve got multiple Gmail accounts, like Clark Kent probably would if he were around today, you can now have them open at the same time instead of going through the redundant cycle of logging out and logging back in.

Google began testing the new feature, which is called “Multiple Sign-In,” yesterday. Previously, the only workaround was to have a separate browser open for each different account. Signing into another account in the same browser would automatically log users out of their existing session.

Now, users can have multiple account sessions active at once, which can be toggled between through a drop-down box at the top of the Gmail page. Users can find the new setting under the My Account section of Gmail.

The same feature is now also in Google Calendar, Google Reader, Google Code, and Google Sites. Other Google services still only allow one account sign-on during a session.

A couple caveats apply when users turn on Multiple Sign-In:

– Using a non-supported service, like Google Docs, may have glitches

– Users will not be able to use Offline Mail and Offline Calendar

– E-mail drafts created in Offline Mail may be lost