Social Networks. Are they the brand or do they just support the brand?

There are a few types of social networks.  Those that support a brand and those that are the brand.

MySpace (www.MySpace.com) and YouTube (www.YouTube.com) are examples of social networking sites that consumers visit to consume the brand.

Brand supporting sites are those, such as, www.nikeplus.com or www.dove.com.  These sites providevalue and add value to the brand, but aren’t the primary purpose of the brand.  The Nike brand purpose to to provide footwear and sports apparel.  The Dove brand provides personal care products.  Neither of these have a primary purpose of providing a social network. 

Do you know of any other types of sites?  I’d love to hear from you.  Please let me know.