If you are one of them, you should change your password: go to your UserCP or use the Forgot your password?. Furthermore, if you use the same e-mail address and password combination elsewhere, you should change it there as well.
"I have some unfortunate news to pass along," the post reads. "Yesterday I was informed by our sever/developer team that the server hosting Androidforums.com was compromised and the website's database was accessed. While the breach is most likely harmless, there are important and potential pitfalls, and we want to provide as much helpful information to our users as possible (without getting too technical)."
Phandroid will continue to investigate what happened. The exploit used has been identified and resolved. All code that resides in the database and the file system has been thoroughly reviewed for malicious edits and uploads.
Recently, the social Q&A Web site Formspring said that it was the victim of a hack that yielded hashed passwords for around 420,000 of its users. Yahoo warned users of its Yahoo Voice service of a breach in which 400,000 plaintext passwords were stolen from the company and posted online.