That was the other thing I noticed. On those forums, it seemed the majority of affected people had a trojan on their PC which was stealing their FTP info. Then another (compromised) machine, or even their own compromised PC, would use this FTP logon to grab their source files, edit them, and put the edited files back on the server.
So then the people would see their server files, their website, was corrupted, so they'd do a restore from a backup & change their FTP password. And the very next day their site would be corrupted again! Some of them got very very frustrated. Who can blame them.
Finally they'd work out they had this trojan on their PC. They'd get rid of the trojan, change their FTP password again, restore their site from a backup again, and life would return to normal.
Sounds unpleasant to me - be a good thing to avoid.