I don't know where Logan got his from!
The one I posted was a smiley on the Something Awful forums at first and you typed something like :faget" or :faggot: or something like that for it to show up. 4chan started using it as "awesome face" and it is really just mostly used in photoshopped stuff.
It's not bad lol. Just understand anything can be posted; the goriest shit and the worst type of porn without any hesitation. If you're desensitized you'll be fine. And no, it doesn't show up very often.