Firefox 4 may be still new, but Firefox 5 is already being prepared by Mozilla. At least the UI features have been laid out by the Mozilla team — there are nine new features in total. There are some features that are replicating Chrome functionality (tab multi-select or an integrated PDF viewer that will also extend to other file formats), but there are completely new features such as tab web apps, an identity manager a home tab that replaces the home button as well as a social sharing feature that is integrated in the URL bar and enables users to post directly to their Facebook and Twitter pages."http://news.slashdot.org/story/11/04...Tab-PDF-Viewer