Hardcore Gmail users have been waiting for quite a few things from Google , but few are higher on the must-have list than this. In the past few hours, the Big G has quietly enabled some accounts with a multiple account sign-in option, which -- as you'd surmise -- allows users to sign into more than one Gmail account within the same browser. In the past, users had to use all sorts of tricks (or worse still, a secondary browser solely for their secondary email account) in order to view various identities at once, but now it's as easy as selecting the option and tagging a drop-down menu. Sadly, committing to this sort of sorcery has its drawbacks: Offline Gmail and Calendar will both be disabled (and this doesn't work on mobile devices), and there's no time table as to when those kinks will be worked out. For now, most of you will have time to think it over as you wait for your account(s) to be activated -- everyone else has no excuse for twiddling their thumbs.