The case of the bleeding monospace font!
I don't know why is it like that, but I like it :)
This is the only question that looks like that.
Here's another for comparison
What could it be
I'm not sure exactly what is going on with that answer, except for the fact that a tag isn't being closed correctly by the SO engine. For some reason, your post is being cut off prematurely, i.e. parts of your question are actually missing from the source (and the rendered output).
I would suggest that you copy the entire revision and try pasting it into your question. Hopefully, that'll fix it. If it doesn't, then I would attribute the problem to the engine, since the markdown code you're using looks fine to me.
Yes, I noticed that too. It happens, under certain conditions, when the font from the Markdown Editor bleeds into the page below it. I've seen it before. I'm using IE8. Switching to IE compatibility mode makes the problem worse.
You will note that the problem goes away if you remove the
And yes, I also like that font in the tags.