Why does my profile state that I joined in Aug. 2009....
Why does my profile state that I joined in Aug. 2009 when in fact I joined over one year ago in 2008?
It's the same for all of us -- nobody's join date is correct.
There's an error in the system and the administration is aware of the problem. I'm not sure whether this will be fixed unless they get more tech help.
There are two dates - you joined 18 Aug 2008 (guess how I know?)
28 Aug 2009 is probably the last time you changed your login name/avatar/anything else in your profile description...