Today I experienced a very weird problem on a blog running WP2.7 - the names of all the commenters simply became anonymous. There were no plugin/core updates done, nothing. I looked into wp_comments table, and realized that wp_comment_author became of value 0 for all the comments. I'll figure ouut how to recover most of the names using my backups, but I am really interested what could have happened. I understand that it might be simply a hack attempt (although why would you do that?), but maybe it's a problem with WP core or smth?
Some relevant features of the blog in question:
a) Policy "a user must have a first comment approved" is in use.
b) The blog is very comment-heavy. It receives ~50 comments per post, currently having ~9000 comments in total.
c) It uses Akismet for fighting SPAM.
d)There are two more comment-related plugins (but they do not look harmful): simple trackback validation & subscribe to replies via e-mail.
Would be glad if anyone could speculate why and how it could have happened (I understand that basically you only need "UPDATE wp_comments SET wp_comment_author = 0", but why such a query was executed?), and if anybody could provide solutions how to prevent it from happening again, I would be extremely happy (maybe some cool MySQL locking, smth?).
And finally - does anybody know how the policy "a user must have a first comment approved" works? It looks like all the comment authors have to be re-approved again, which is strange as IP/e-mail/url information remained in the SQL tables..
Thanks a lot.