Fox Interactive Media recently released a 68 page study about social media. While this study mainly focuses MySpace (and almost seems like an advertisement at the beginning), it has some important information for PR.
The study discusses how social media users (particularly MySpace users) are discovering -- and building relationships--with brands and products. In fact 4 out of 10 users reported discovering brands through social media. The majority of this discovery occurs through the momentum effect. The momentum effect is when someone posts or blogs about a product and their "friends" read that information and go on to use the product. Therefore, the study recommends companies releasing transferable links, pictures, backgrounds, etc. for consumers to use on their own websites and blogs.
Along the same lines, the study found that what consumers want is "friendonomics." They want companies to treat them like friends. Tell them information that is useful like what specials are occurring or if a new product is released but not to overload them with boring, unimportant information. The tone is also important. It needs to be authentic.
The study held more information that was rather interesting and presented with fun graphics. It even gave profiles of different types of users (go see which one you are!).