Ben Silbermann and Evan Sharp, co-founders of Pinterest, both used their prior experiences in the technology and the internet to start a very successful business of their own. Silbermann was a Google employee until he left to design apps on his own. However, these failed to gain any traction, until eventually he designed a product inspired by his own love of collecting things.
Similarly, Sharp worked at Facebook as a product designer. He met Silbermann in New York, and then joined his team to make Pinterest a reality.
Pinterest is really about idea sharing. People enjoy telling others about their ideas, and Pinterest gives them a platform to not only do so but also to gauge how a community will respond to it. It is a great place to see other peoples ideas as well, and find inspiration for many different things.
This business idea is a great example of collision in a liquid network. In the realm of technology and the internet, two men with the experience and ideas necessary collided to make a business that could possibly eclipse Facebook and other social media giants.
Without one another, the idea would just be a pair of hunches, and nothing would have come from it. However, in a community where ideas can bounce around, change, and grow, true innovations can be born.