Here's an evernote file of things I've found and liked around the internet re: 2 sided marketplaces. All digital, although not sure exactly how "successful" they are - but more for reference.
How it works
This Nov 2012 blog post by Bill Gurley of Benchmark Capital is very insightful, and cites some great examples as well:
All Markets Are Not Created Equal: 10 Factors To Consider When Evaluating Digital Marketplaces
Also, see the deck here which takes Bill Gurley's ideas above and translates them into an evaluation framework: