Stephen Downes has a very interesting take on all those open API's that are available in today's world. Check out his article, titled Six Basic Truths of Free APIs, where he references George Siemens also.
This is the summary: "You seem to get a lot more functionality coding on top of Google search or Google maps. And yes, a lot of people are coding for, say, the Google API instead of creating open source applications. But as the article notes, if you live this way, you live only with the blessings of the company that created the API - and as we've seen, even with Google, such companies can be very self-serving (whither the Atom API?) and fickle."
This is the summary: "You seem to get a lot more functionality coding on top of Google search or Google maps. And yes, a lot of people are coding for, say, the Google API instead of creating open source applications. But as the article notes, if you live this way, you live only with the blessings of the company that created the API - and as we've seen, even with Google, such companies can be very self-serving (whither the Atom API?) and fickle."