What do you call "mature content?" Google does NOT like adult content. Nudity, sexual content, etc...not allowed.
It's a risk, because the rule isn't just "no porn" it's "no non-family friendly content". If it's just one post out of 100s, you are probably OK. First off, if you have a question you should start your own thread. No fair hijacking someone else's. Secondly, no you can't add Adsense ads to a Facebook profile or Myspace profile. Those sites don't allow you to post javascript, so you literally cannot do that. (It's different if you've written an app for Facebook - those can have ads).