I was a developer/founder once. I partnered with another developer, and we made a tool that would track the ranking of your site in regards to certain search terms, to a.) figure out whether your SEO guy was worth the money, and b.) figure out which SEO tricks worked best.

We weren't really making any money ,so I sold out my half of the company to a business guy. My former dev partner then went on with the business guy to make it a half-million a year business with about 4 hours a week of maintenance work.

Of course, I truly believe it wouldn't have gone anywhere if we didn't bring in a business dev guy, and I can't see any reason in retrospect why I should have expected their business to do so well once I left, but...

Seller beware! :-)