Earlier quoted context omitted.
Thanks! I guess to me, more important than the selling price, was the process as a whole. It's a product that I took from an idea, built out and eventually sold. In there were a lot of lessons that I thought might be interesting to people. $3,500 might not be a lot to you. And obviously it's not enough to go away on. But it does mean that I can work full-time on my startup this summer.
I thought the post was great. $3,500 is better than the $0 that most people get for their side projects. Congratulations on the sale and it sounds like it was a great learning experience. edit: If you don't mind sharing, how did you end up finding the people who were developing their own sites? The post mentions customer engagement but not how you found them in the first place.
I basically ended up doing no marketing for DomainPolish whatsoever besides a few posts on my blog which were popular on HN. A few other people tried out the service and wrote popular blog posts as well. I think doing the thank you videos in the beginning was key because it gave people a huge incentive to tell their friends about the site.
I wish I had more to say on marketing but that's something that I'm working on a lot now for my new startup. Hopefully in 6 months I'll have some more lessons to share :)