Application Programing Interface, in short, API is very common term for any software professional. Once, one cross "Hello World" or "This is my first program" in the programming worlds - you get to the world of APIs. These low level programing constructs are becoming business drivers in the world of web beyond browser.
Look at these 3 company in this space - Apigee, BlueVia & Mahery. They all manage APIs and help developers in building application using these APIs. Intersting enough that BlueVia is a spin off from Telefonica - a large telecommunication company.
ProgrammableWeb, directory of API and Mashup listed 3375 APIs and 5886 Mashups as on today. You can look for API and start using.
So, is this is a new business model? From developing a web to developing APIs. API-as-a-Service. Looks like future will be on using the APIs to mine the data and build innovative apps based on these 2!