This is one of those "Has this been done already?" idea questions.
A browser that analyzes the search results, conversations, stories etc. to estimate whether it was created by AI or not.
This would be done by using those algorithm thingies and like, computers and stuff.
So you find a person
on a chat site and start debating about something stupid, your browser plugin will say "Hey, that pointless argument you're having about that stupid subject? Might wanna chill out, that's an AI program pretending to be a person."
For the truly sad cases, it might pop up "Hey bro, your "girlfriend" "lives" on a server someplace, she's not real. (click here if you don't care) [_]
A practical use might be for teachers. "This student paper was written by Cheatbot 9000."
Again, I'm kind of assuming there's something like this out there but I just haven't heard about it.