Any site that asks me to share <i>before</i> I've viewed gets a big fuck you from me and I'll just leave. It's ridiculous and completely ignores the point of sharing. I don't see the cover of a film and say "Hey friend, you should watch [film], it's awesome!"... because how can I know it's Awesome? I haven't seen it. The same goes for any sort of web content, I am not sharing content unless I <i>enjoy</i> it and I can't know that before I have viewed it.