Robert Young says in GigaOM that self-expression has become a new industry. I'll just give you the quotable bits:

• the art-form of self-expression has become the “new media”, and social networks are their distribution channels
• for any player who seeks to enter this industry and become the next social networking phenom, the key is to look at self-expression and social networks as a new medium and to view the audience itself as a new generation of “cultural products”
• For traditional media companies that are seeking to enter this space it’s critical to follow the audience into the development of this new market by re-focusing core assets that have the capability to deepen the level, and heighten the production value, of self-expression