Some time ago, I had blogged about a stite that allowed you to clip portions of webpages. Well looks like that was not the only one website that allowed you to do that. Here's another one and this guy goes far beyond just clipping and has a range of products in the area of social annotation, bookmarking etc. The link is here.
There's tons of social networking sites. Well, here's another one. perfspot. Make sure you check out the perfNights section. It's hot.