The Gmail Manager Firefox extension is a time saver for everybody and in case you aren't using it already you'd better start right away. Besides letting you know when you've received a new Gmail message it also lets you switch between Gmail accounts without having to sign out and then log in again. With the time it takes Gmail to load all the messages on lower-end machines, that's no feat to be taken lightly.

You would still have to add your Gmail accounts and Google Apps accounts though, but after that after that it's as easy as pie: you select the account you received the new mail on by right clicking on the Gmail Manager icon in the status bar and then left click on the icon.

Of course there are several other modes to switch easily between your Gmail accounts, as Ionut Alex. Chitu of Googlesyste.blogspot.com noticed, like the Google Account Multi-Login Greasemonkey script, but this stores the passwords in a non-secure way so in case you're using one of the Gmail addresses as your primary, you'd better stay clear of this one if you're not sure.

But there's also a third option, if you don't want to be switching back and forth between the two addresses all the time: you could just forward all the messages from your secondary to your primary mail account and enable it to send messages using custom From: addresses. If that's the one you choose to use you should again thank Ionut Alex. Chitu for the idea.

Like I said, a huge timesaver and also a reason to not clear your private data every time you sign in from your work computer. Who's going to suspect that you're doing this? Hmm… perhaps somebody who is doing it himself, but come on, what are the odds?

Once again, the Gmail day is saved thanks to… no, not the Powerpuff girls like you might have thought but to the open sourcing community that's working for and with Mozilla and Firefox!