I continue to be stunned and pleased with the huge growth of API usage. At the recent Apple event, one statistic they shared was that there were 150 million users who send over 1 billion messages per day. A big driver of that usage is applications. It indicates that developers are seeing ever-increasing value with APIs and also looking for new ways to differentiate their apps. I am also seeing huge growth in APIs—ProgrammableWeb does an excellent job gathering information on APIs. There are over 6000 now and they are being added at a blistering pace (most of them RESTful).
As expected, the companies delivering the highest volume of APIs include Twitter, Google, Facebook and Netflix. However, AT&T does well with API delivery—we are fourteenth overall (source, ProgrammableWeb presentation, http://www.slideshare.net/jmusser/j-musser-apishot
Now the challenge to developers is what APIs to use and to balance any cost for the APIs vs. the return they will see. This can be a definite challenge, particularly given all of the variables they must balance and feature decisions. There is little doubt in my mind that the best apps will include some significant API integration and that each new API and perhaps even mash-up.
One other area I want to comment on is privacy. If developers are not aware, user privacy is getting greater government attention—for example they are asking storefronts to require apps to follow certain privacy guidelines. Now, I know developers are pressed for time and resources, but this is a good thing and need not be a ton of additional work. Recently, A mobile app developer was sued by New Jersey and had to agree to stop collecting and transmitting personal data taken from children who play its popular educational games. We have some information on our site then the GSMA has some good guidelines here: http://www.gsma.com/publicpolicy/mobile-and-privac