I just resolved a rather worrisome case of spam in my blog. As opposed to unwanted comments showing up in each entry (which is a manageable problem), There were spam links appearing directly in each blog entry! Specifically, every end-of-paragraph on the page had a spam link added to it.
After much searching, I realized that only the actual outputted HTML pages were affected - the database entries and Movable type code was unaffected. So simply rebuilding the pages fixed it.
But that's very troubling, since that means the actual HTML pages were changed on my site! That implies someone gained access to my files on my web host and changed them. Indeed, when I check the other sections of my webpage, they have the same type of spam inserted in their text!
This is going to take some time to correct, and I have no idea how this happened in the first place. Perhaps I need to change my site's password, if indeed it has been compromised. Still, if my site was compromised like that, I wonder why I didn't see entire pages replaced with spam ads, instead of just adding a small link to the end of each paragraph.
Ah well, for now, I'm going to start cleaning up may pages and making sure I have a clean backup. Wish me luck...