It's not a low-budget sales force, or a way one person can do the job of three. In other words, it's not the answer to all your prayers. If you're at the point of praying, then the business model is the one needing help.
Social media is a tool, just like the telephone is. It's not even marketing -- in the traditional sense, marketing is dead.
What social media does is simply allow you to do one thing: communicate. That's it. Social media is not the conversation. It's the room in which you hold the conversation. It still comes down to saying, doing, or producing something valuable for your customer. Companies which forget this will simply throw money down the social media hole. Companies that get it will find social media a valuable tool -- if they they are prepared to stick it out and learn how it works.
Who says business has changed? It has not. Fundamentally, business is still all about people, products and services.