Millions of businesses have jumped on the social media express train over the last 12 months, but many of them do not know why they have a Facebook account or why it is so important that they have a presence on Twitter. Even those companies that have dedicated personnel in-house to work on their social media presence often struggle to justify the investment -– all they know for sure is that they ought to be participating in social media, often as part of their SEO efforts.
http://www.searchmarketingstandard.com/develop-social-media-strategy-2010