The information contained in that database includes androidforums usernames, email addresses , hashed passwords, the IP addresses members registered with and forum group memberships, among other data.
“This was, in our current opinion, most likely an e-mail harvesting attempt. A spammer could theoretically attempt to bulk e-mail all AF users with the user database. Luckily, GMail and similar e-mail services offer a “spam” button that helps it to collectively identify and automatically filter potential spam,” The security notification reads.
If you are one of the user, Change your password now: go to your UserCP or use the Forgot your password? function. If you use the same e-mail address and password combination elsewhere, you should change it there as well.