Source: Battle.net

tl;dr: Real ID required to post on Blizzard forums. Real ID is a new Blizzard feature that shows your first and last name and accounts on all Blizzard games. These changes will go into effect on all StarCraft II forums with the launch of the new community site prior to the July 27 release of the game, with the World of Warcraft site and forums following suit near the launch of Cataclysm. The classic Battle.net forums, including those for Diablo II and Warcraft III, will be moving to a new legacy forum section with the release of the StarCraft II community site and at that time will also transition to using Real ID for posting.

My comments: Awful idea and thousands of people have already voiced their opinions on Battle.net. Posting on Battle.net forums with Real ID can be linked back to account sales pretty easily. Be careful.