MS have this?
This sounds a great deal like something Microsoft have - called API management, in Azure.
Lets say you're the BBC. You have lots of data with a set of services to return query results. You want to sell this, with maybe different rates for the number of queries per month, more detailed results = more money etc. You could build your own tool to manage this stuff (with the analytics) or you go to Apigee.
The valuation is presumably based on speculation that this will become a big money spinner and Apigee will get a slice.