Just my first impression: can't you use Google Analytics API to see the inbound keywords people are coming from (so users don't have to add another tracker) and use, for example, AdWords API to generate similar keywords?
People could use the GA API and Adwords API to build something similar. But that just goes into the argument of whether to build or to buy. Businesses would probably spend the money instead of building it themselves and wasting their engineer's time.
Tell me if you have any thoughts on my response. I'm thinking I really need to clarify the landing page but I'd rather finish building the MVP.