The action taking place on the battlefield is just one part of the StarCraft II experience -- we're also working to make sure that you can easily connect, communicate, and play with your friends. To help accomplish that, the new version of Battle.net will offer integration with Facebook. This new functionality will start off by allowing you to quickly import Facebook friends into your Battle.net friends list, and additional features will be added over time. For more information, check out the official announcement.

http://eu.blizzard.com/en-gb/company/press/pressreleases.html?100505