I've talked about Pownce before a few months ago when talking about the new face of the web and how social networks have become an important and habitual part of anyone's routine online. Pownce was started primarily by Leah Culver, Daniel Burka, Kevin Rose, Ariel Waldman, and Shawn Allen who may sound familiar from their work primarily with digg.
I had mentioned that Pownce was in private beta at the time, but now it's an open beta release including their Adobe Air client. I have always, since the beginning enjoyed the sense of community on the site not only because people can exchange messages or micro blog like Twitter, but people can share files, images from Flickr and Zooomr, clips from Youtube, and even share events with any circle of friends. Most of all, I like the interface, it's comfortable and pretty easy to customize.
I hope more people sign up for Pownce, and that they remember to add me as a friend!