Mac OS X only: Freeware application Fluid runs your favourite webapps in a dedicated, WebKit-based browser so you can run your most-used webapps just like they're native Mac apps. If this idea sounds familiar it's because Mozilla has tackled similar territory with an app they're calling Prism. The major difference is that Fluid uses the same rendering engine as Safari and gets that native Mac look that's still lacking from Mozilla apps. And since Prism doesn't really work with extensions yet, Fluid seems like the best choice if you're on a Mac. Fluid is freeware (though this beta expires in April, so it may go shareware in the future), Mac OS X only.