I also feel that pictures of the actual ceremony are not "my" pictures to post, nor are pictures of the cake, etc. Me and my friends on the dance floor having fun (maybe the bride is in the group or in the background) - why not post? I have not posted anything from the wedding, nor have I seen anything on FB from anyone except one professional picture of the happy couple.
My personal rule is that pictures of things are okay to post as long as they are appropriate (such as I would never post a picture of someone that is intoxicated, children, etc). I don't post much, but if someone takes a group picture at a party, it usually ends up on social media (and sometimes, someone will say "Nice picture, Ill post it to Twitter!").
I hate to go so far as "everyone in the picture must okay the picture before posting" only because, what about people in the background. I take a picture of me in NYC - there are many people around me and, inadvertently, in the shot. Do I go up to them and ask if I can post the picture? This instance is different than a party because I am in a public place where you do not have the expectation of privacy.
Should someone not like a picture of them for what ever reason, I would happily take it down immediately.
I'm glad to read both sides of this issue, there are some great points made!