Ghost let loose in my Bloglines account?

Something really weird is happening with my Bloglines account. All of a sudden I found two new feeds I certainly didn't add myself, in fact, had never even heard of before: one Didier Stevens and one Panzera Security blog. Very strange. Then, the next time I checked my newsreader, Didier Stevens was gone but to my surprise I saw that one of the feeds I do subscribe to, David Black, had 10 new posts. Upon closer examination I found that this Didier Stevens feed had inserted itself into David Black's feed, and the former was clearly advertising for various software solutions. A new sophisticated form of spam? I'm even supposed to have saved one post from the Panzera Security blog which I have never opened. Spooky. My mind needs some rest after a long days' work now, but would be grateful for any suggestions of what's up here ...