A great way to acquire new customers is to take your existing database and ask a data company to supply you with "look-a-likes". These customers will have similar characteristics to the ones you already have. If you're starting from scratch you can tell the data company who you'd like and they can supply that for you.
Problem is that these people are cold. They've never heard of you or your service, or they'd already be customers. A great idea is to begin to spread your product/service by piggy backing your product with something that similar customers will buy.
Great idea if you have something you can distribute free. If it's close enough you're getting your self into the hands of the right customers without giving them any risk. If you're close enough they become your marketing strategy all on their own. Seth Godin sums up the idea here.
If you're small enough and the product fits why not try it?