This is a topic that is debated daily.
WHAT SOCIAL MEDIA INCLUDES: For many, the term "social media" includes blogs, microblogs, photo & video sharing, podcasts, ratings & reviews, social games, social networks, virtual worlds, wikis, etc.
Be cautious when reading 'social media'; definitions vary.
BEGIN WITH THE END IN MIND: Each company/team must define its success. Since social media is a mechanism/tool a bit like a Swiss army knife, it can be many things, used in many ways.