Firefox 5 New Features

Although Firefox 4 has just recently arrived, Mozilla's development team is already hard at work in the upcoming Firefox 5.

And it looks like Firefox 5 will have some interesting festures, although some may eventually get pushed back to future versions.
Firefox 5 will have integrated preview visualizers, for things like PDF files and even MP3 audio files, and learn some new tricks: like the ability to select multiple tabs.

More interestingly, it will have an integrated identity management system.

This will allow you to be logged in into your social network sites, like Twitter and Facebook, and even have multiple accounts active at the same time.
I don't know how they'll pull it off, in order to make it "easy to use", but I sincerely hope they succeed (and if it works for multiple Google accounts at the same time... the better!)

(And yes, I know I could use the multiple Google accounts feature right now - but I'd really prefer having my separate Google accounts separate.)