As mentioned in this post, I’ve been getting “spimmed” (instant-message spam) via Skype from a particular English-challenged person. I had switched my copy of Skype to known-contacts-only mode and thought nothing more of it.
Until last night, when I received a fourth copy of it. How it got through my privacy settings, I have no idea.
I specifically blocked the username it had come from this time. Hopefully that will be enough to stop it.