That's one of the concerns I have. I know that the iFrame attack has been around a number of years. I know in '2006 there was a rash of injections and that was mainly due to phpBB and postings on there, and in March 2008 there were some issues on Wordpress, but was later determined that it was when people allowed COMMENTS and the hackers/exploiters were just posting in the comments section. That was resolved by killing HTML codes in the comments area.
I'd be curious to see just how many things are in common between the various sites.
As a note of warning to those who are reading this thread and have not already done so -
please change your passwords! http://strongpasswordgenerator.com - this is a decent site for generating passwords if you don't have a password generator on hand.