One of the first posts I ever wrote (back in December 2010) was about compounding introductions. The concept is that if you get an introduction to the right person, that introduction can lead to multiple introductions and have a positive compounding effect.
The same concept happens with partnerships. I experienced this first hand at Aviary and now again at Dwolla. Typically when you have someone integrate your API, if it is done well, other people will take notice. If it is relevant and helpful for them, they will also want to integrate. And on and on.
This is why I like launching new products WITH companies rather than just the product by itself. While this might delay the launch of a product by a month or so, when people see the integrations it has a compounding effect. Launching the product alone, with no integrations (if your business is partnerships/integration-driven), is not ideal as companies want to see who you are already working with and where they can use it today. There are no good excuses, from a biz dev/partnership perspective, for why you can’t point to anything.
Bottom line: Launch integrations with partners. Those partners will help compound integrations and validate your business even more.