Something I learned about Twitter, how powerful it is, tweets are basically people's thoughts. Same thing with Facebook updates. Advantage of Twitter is that it is public (unless you have private tweets only, which is <1%). I have used Twitter search in the past to find my exact target markets. It is fantastic. You can really learn a lot and you get direct to the source. For example, you might have a site about body piercing. So just do Twitter search for keywords like: "stretched ears" "stretched lobes" "gauging" etc. Suddenly you find your target market! But how can I spam these people? I would love to automate the process. The return on people following you back and seeing your link and then your tweets is very low. So it seems the only way to take advantage of this method is to go for mass spamming. I hope this info is useful for you. Now please share with all the best way to monetise these people on Twitter!