I see and hear it on Facebook statuses, in comics, in pretty much every TV show, in the hallways at the university, even from students in grades 5 or 6 at the schools I go to...everywhere, actually.
It's so common that people don't really think what they're saying is incredibly insulting and insensitive, as they would if they were being racist or sexist (though, we all know those are still issues as well).
Here's a newsflash to all the lame-asses that still think it's funny: this shit is not acceptable. Don't say something or someone is gay, or a faggot, or a homo as an insult. It's considered hate speech. Stop it.