Much already been said about the new Real Id system Blizzard plans to implement. While it won't affect the game directly like I pictured, the barrier between your fictional char and your real self got thinner.
If you are bold enough to post on the forums with the name of your character also included (the Real Id, your real first and last name are mandatory) it will be easy to track your character to your real person.
How bad or good it will be depends of how much of your personal information is avaliable and how devilish a potential player is willing to go to ruin your life. Women in special surely will have something extra to worry about now. Other people may find their own reason to keep their WoW hobby private.
Given how... involved, some players are in WoW, who knows what they can do if they find that N. Elf Hunter who just ninja'ed their epic loot live across the street. Would you like people this guy to know as little as your name?
Surely pays to point this is a 180 degree turn from the previous ruling which gave a instant, perma-ban to whoever exposed another player personal info. I am sure these harsh rules were there for a reason...
For me, at least, it changes nothing. My characters are usually well know and I never found any problem. Your mileage, however, may vary.
To close, I'd like to point there is a good side of it!
I just can't think of any at the moment.