Yahoo's TOS for groups.
http://docs.yahoo.com/info/terms/
I'm not a lawyer but it reads to me that it places the responsibilty onto the user. I guess the question would be obscene.
There are hundreds of platforms allowing users to share photos and videos. There must be a way to do this and keep it legal. If a person signs up and agree to the TOS stating that they are the keeper of records, how is that any different then if I purchased content from a broker and they simply give me a license agreement stating they are keeper of ID's and records?