Amazon's cloud-computing business has steadily added customers since its inception in 2006. The company periodically provides updates on the number of developers using its web services, and based on the latest figure, Amazon is fast approaching the half-million mark. That's a significant milestone for Amazon, which has been pushing to grow web services in the face of growing competition from Microsoft, Google and others.

The Amazon Web Services blog recently counted 490,000 developers in its program. That's up from 440,000 the last time I checked.

While the number itself may be impressive, there's a lot more about Amazon's cloud computing business we don't know. How many of those developers are web startups -- who were among the first to test web services -- and how many are large enterprises? Amazon has been making a push for bigger companies, many of which were initially hesitant about cloud computing because security adn reliability concerns. Amazon, however, has never broken down its web services customer base. Andy Jassy, the senior vice president for Amazon Web Services, said in a recent interview with TechFlash that "enterprise interest in adoption is happening much more quickly than we anticipated," thought he didn't give specific information beyond a few examples.

Another question: how significant are web services as a business segment for Amazon? As I noted earlier this year, Amazon lumps its web services business together with other categories in its financial reports, making it difficult to determine how the cloud computing segment is doing.