i have been wondering this for ages. Please let me know if you ever find out .

The most likely culprit is that the art in question is adult/mature. People can choose to have all adult artwork in their faves hidden.

Or just hide their faves altogether.

^ This

I never understood the logic behind it.

Are people ashamed of sharing what they like? I'd queried someone about it once after they faved one of my pics. "I'm trying to keep my page clean" was the response, but several adult pics in their own submissions @.@

I can "sortof" see that people don't want to be seen as "wierd" but people, you're on a furry art site. Not gonna get much wierder :P

I don't know about others here but I have it set so that only those who watch me can see my favs as that let's them know what I typically like and somewhat prevents a bot from grabbing my favs though that doesn't stop them from watching me here.

Maybe it's people who want to tell the artist they like it but don't like filling up a fave gallery? I usually leave a comment so mine doesn't get full of all the same thing.

Really? How do you do that?

I have no idea. I think it might be in the user settings somewhere.