In my knowledge i dont think its possible to message each others and the type of forums are about homebrew development news or stuff.
Hope u understood
Ok, I just wanna show u guys "my" suggestions on a new concept which was a classic app/program in the ds,ds lite and dsi.
'Pictochat' should be remade for the 3ds but instead of using wireless communication built in the 3ds....we can use internet to communicate.
Maybe make forums inside 3ds...