Having the string "WebObjects" in the URl:s should be a pretty good indicator; https://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore...

It's well known. An extract from Wikipedia:

"Apple is now the biggest client for WebObjects, relying on it to power its online Apple Store, MobileMe online services, and the iTunes Store."

I can verify that the iTunes store and Ping use WebObjects.