I've totally blown my anonymity. I've done everything but post my face and my tattoos as avatars. When I park in the school lot the first day, people are going to be like, hey, look, that must be Promethean... check out his sweet ride!
But, I haven't been a raging jerkface to anyone, and I have been willing to admit and apologize for mistakes when I have put my foot in my mouth. I find the best protection against having your posts used against you is to behave the same way when you are "anonymous" as when you are acting under your own name. Then, when you are found out, you will have nothing about which to feel embarassed or concerned.