I don't know what else they did, but smartystreets.com did a great job with word of mouth. They would find forums with questions about address correction, and

I don't know what else they did, but smartystreets.com did a great job with word of mouth. They would find forums with questions about address correction, and provide great answers that DID NOT require using their software. Then just put their site in the profile or at the end of the post in a tactful way. I started using them based on the expertise in these posts.