You can use the social API's to get new customers. One way is with Twitter's API. You can filter tweets for keywords and then friend the tweeters. That's what's happening when you tweet something and then you get followed by someone of that special interest.

I tweeted something yesterday about birds. Today, I found I was followed by @artmagenta, an artist who draws birds. You can bet he's got a filter set up to find tweeters who are interested in birds.

OSCON 2012 featured a talk on extracting data from Twitter using Python. The speaker said he'd post the dozen or so Python scripts on the OSCON site soon after the conference. Those scripts would be a healthy jump start to anyone who's interested in finding new customers on Twitter, or generalize them to do all sorts of stuff.

If you look him up, please post a link to what you find here as a comment!