I don't understand malicious mischief.
I joined Fotolog several years ago. It was a nice, friendly place where people could share their photos and get to know other photographers. Then it got "hijacked." It started with Brasilians upset that the Fotolog had no structure converting Brasilian currency, and that the conversion rate was so favorable to the USA that it would cost them the equivalent of half a month's pay (or something like that) to join.
So they set out to ruin Fotolog. They would fill up guestbooks to the maximum with ridiculous messages, they posted terrible photos, rude photos, very bad quality photos, and they did everything they could possibly do to crash the system, which happened regularly. I finally got tired of dealing with it and moved my photos to dBase.
But then I discovered Flickr. I really like the structure--I like being able to be part of groups, to get involved in conversations with other photographers my own age.
Now a group has decided to "pee on Flickr." They are doing this by posting lots of yellow photos in various groups. It's not quite the disruptive influence that we saw on Fotolog, but there are people out there who are bound to make things unpleasant for those of us who just want to share our photos.
What in the world do they get out of it? The power of making thousands of people miserable? There's got to be a better way to do something meaningful in your life than to laugh at how much trouble you can cause.