I realize that we have very few comments here and most of those come from a mentally ill Canadian.
Well, due to the slight annoyance of the spammer I have implemented a free comment system from disqus. To comment you must have a free account at disqus (single sign-on with multiple registration services, such as WorldPress and typepad may follow someday if this blog ever takes off with lots of comments - I can dream, can't I?). After I installed the new commenting system I deleted all the crazy Canadian's junk.
BTW, this is the person who coined the now (in)famous bit of word salad: GOATS ON FIRE! Yes, in all caps followed by an exclamation point without any context whatsoever - entertaining, but not for very long.
Blogger does not offer any way to block or ban commenters. Sadly, the realities of life on the internet make this necessary. At this point, only spam and the overtly mentally ill will be banned. If we ever actually do have discussions which attract trolls, I will use the PZ Myers POO test.
For the moment, we can list this one under problems we wish we had.