Social Media Marketing - Is It Possible To Measure Return On Your Investment?
http://cashmfbz144.tearosediner.net/key-take-into-account-remember-in-linking-dollars-and-twitter-account
You put a link in your tweet into a CPA (=Cost-Per-Action) offer. If you're seen as friendly and approachable, more people will want comply with your account and your opportunity.