There's this relatively recent feature (since autumn 2012, I think) that venues have a score, apparently in the 1-10 range.
I mean the "8.7" in this screenshot:
...and the "8.1/10 People like this place" here:
Now, foursquare doesn't allow users giving any numeric venue ratings. What you can do is "like" and "dislike" a venue (along with saving them to lists, writing tips, and checking in, of course).
Also, from what I've seen, liking venues is relatively little used feature and I'm quite sure that a score of 8/10 doesn't mean that 8 out of 10 people who checked in also liked the venue.
So, my question is, how exactly are users' likes (or other actions) converted into the venue score?