Since we use their e-mail obfuscation feature, the TW sites are among those that could potentially have been affected.
Just as a precaution, I've cleared forum sessions, so people will need to login again. Based on the information available at this point I think it highly unlikely to have really been necessary, but having to log back in is a minor inconvenience, and it's better to be safe than sorry.
Due to the random nature of the spilled data by CloudFlare and the apparent extreme infrequency of it popping up, I think the likelyhood of anyone on the forum being affected is very low. By far the most likely thing to have been compromised would be a session key since most people stay logged in (and your login info is only transferred whenever you directly log in, not while you've stayed logged in), so that should be taken care of.
Any users feeling especially cautious might consider changing your password for the forum, particularly if you actually log in frequently rather than staying logged in.