Since we can't help but assume that most readers' reaction to Wyzo would be something along the lines of "You can already do that in Firefox," I'll run down some of the best features Wyzo offers and offer the Firefox counterpart (though in most cases the "counterpart" is actually the same extension that comes pre-bundled with: BitTorrent Integration, Download Acceleration, Cooliris Previews. Its a universal appz so you can run it on your mac/pc/linux.
