Eric Heimerman's Public Library

With a sweet-spot strategy, only customers who love your product are of use to you, and you really don't care how many hate it, as long as you and they know why they hate it. You might find a few products that everyone merely likes, and you actually now need to avoid those. In sweet spot marketing, a large number of customers who hate your product may be a good leading indicator of success, if they are accompanied by a few enthusiastic fans.

It is free to use the product and build and test as many apps as you would like but to actually get the binary for the App Store or Android Market, companies need to sign up for the premium enterprise edition that costs $15,000.