[dpcan]

Exactly.

If Facebook wastes their time and resources building and supporting a full-fledged BROWSER, they would be out of their mind. A Toolbar makes perfect sense.

The same way there's a new phone out there with a Facebook button right on the front. They are an add-on.

Building a browser is not just about adding neat social features. People use their browser to do everything - Facebook related or not, and when things happen OFF of Facebook, Facebook doesn't care - not in the same capacity as Google anyway. But if they build a browser, then they open a whole new can of worms.