The Two Plus Two Forums have been hacked, and the forums have been taken down by the admins to prevent further damage. The hacker has gained access to a list of usernames, e-mails, hashed passwords, and password salts. While hashed passwords and plaintext passwords aren’t quite the same thing, the combination of the hashed password together with the salt makes it possible for the hacker to find plaintext passwords. (This is preventable, but vBulletin’s default hashing algorithm is md5, which is completely insecure against this sort of thing–and other things.)
In other words, you should assume that there is currently a hacker that knows your 2p2 username, your e-mail, and your 2p2 password. That’s really bad. This isn’t your standard cryptonerd/privacy nut’s rant that makes you do a lot of work to prevent a potential attack that may or may not come and that you don’t understand; this is a situation in which a very serious hacker has already done the attack. Apologies in advance for the bold and all caps and stuff.
So, right now, here’s what you should do: