"Nivi, a blog I'm subscribed to, was showing dozens and dozens of entries being updated even though there was no discernible difference. However as I started looking closer, I noticed if you view the source, for example on this post, there is are ton of spam links there. You can click the screenshot to the left."
Ok this is scary. Especially if you are running on someone elses server. You might have no idea that all this crap is in your posts. Usually when some software is hacked it is easy to discern, since the hacker usually wants to get noticed. More covert hacking is the dangerous kind. Where a hacker will have reasons to hide what he has done.