"As pointed out by Information week magazine, there are 50,000 developers signed up for Amazon Web Services program, and 8,000 companies and individual programmers enjoying membership in eBay API program. There are roughly 600 application built on eBay API, and monthly eBay serves 1 billion XML (read - Web services) queries, which amounts to 30 million Web services transactions a day. About 40% of the items listed for sale on eBay's U.S. site come in through its API."

(Via ITFacts.biz.)

I wonder what all this represents in revenues?