Odd characters

I occasionally get comments on this blog that don't make it to the comments section as I reject them. They're usually really general, don't relate to my posting, don't really say anything and are anonymous, all of them include characters looking like this:

I'm assuming that my computer is substituting something else for a font that I don't have on my pc and I'm guessing that it's for a foreign language but I was wondering if anyone knew for sure? I reject them as I think they're just spam but I do wonder if I might be wrong.