RockMelt is an interesting social media browser, based on Chromium, which allows you to monitor and use your social networking accounts as you browse the web.
The program unsurprisingly looks a lot like Chrome, and can even use apps from the Chrome Store, but it also displays "edge" panels that can, say, display your Facebook updates, Twitter feeds, RSS feeds and more. Another panel displays your Facebook friends (yes, you currently need a Facebook account to use the browser), and so you can easily chat with them, check your stream, read new tweets and more, without having to visit the Facebook or Twitter sites.
The RockMelt team are also just beginning to create new apps of their own for the browser. Install the YouTube app, for instance, and one click will open a YouTube panel where you can watch videos, search for new clips without interrupting what's playing, create playlists, see your search history, and share videos with your friends, amongst other things.
And, of course, because it's essentially Google Chrome with some custom extensions, you can be sure that the browser will perform well on all the other sites you visit - it's fast, secure and easy-to-use.