Likes, +1s, Faves. They're addictive. They're also incredibly harmful.
Mainly, people who partake of photography-related-social-networking hand out approval or disapproval based on whether or not they like the photographer personally. The personal like or dislike may or may not be based in part of liking some photographs made by that photographer in the past.
If you make a couple of OK pictures, and hand out approval to like-minded people like candy, they will generally reciprocate, because they're human, and because that it how the game is played. After a while it simply becomes a case of 'Oh it's that guy! Great shot, love your work, as always!' as a spinal reflex.
People rarely actually *look* at photos they see online.
- Pretty girl? +1 great shot!
- My friend Susie? Great shot!
- That one guy who gave me a +Disagree? Terrible shot, the... thing.. totally draws my eye and kills the shot!
Actually looking at an image and trying to make sense of it it work, so mostly what we get is "I like it" or "I don't like it" which is, all to often "I like you" or "I don't like you".