Yeah, with their attitude toward their users privacy the first thing I want to do is give them access to ALL my information and emails...  

Social networks essentially obsolete email. This is just a bridge to dead technology the way email-to-fax service was a bridge to a preceding technology, the way services to receive and deliver faxes/telegraphs were a bridge. The next step forward is distributed social networking - getting you out of the "walled garden" for good by breaking down the walls. When any individual or micro-network can communicate with any other via a shared protocol you'll officially be out of that paradigm. Several projects are promising that (notably Diaspora).

*If* Facebook makes this move, it is a sign of an attempt to consolidate a strong position in aging technology because it has reached a dead-end in innovation. This is the kind of move that a mature business makes, one that is no longer interested in breaking new ground. It's a defensive play, and a good one, but also a signal that we'll no longer need to bother looking to 1st generation networks like Facebook for an indication of where things are going.