@dawgofdawgness always. back up. YOUR WORK.
Yes, non tapas people can see the forums.
I've been having the same thoughts as you. Tried going back and cleaning up my forum footprint... only to find that I could no longer delete my super old posts. (luckily I don't really post anything too out there... but I've replied to a good chunk of wonky stuff.)
Another thing, this isn't my first account on the forums, so even if you delete your forum account (don't) all of your posts will still be there, under whatever username you delete it as. unfortunately, I failed to change my username to something less... similar to my current one.
one thing you could try is flagging your "naughtiest" posts and leave a detailed note for the tapas staff. or your could email them. or change your username to "defunct account" or something.
or get a new account.
my, my, aren't I chatty today?
edit: oh snap, everything's been said already.