Bumped into this gem of a post by Andrew Chen, a silicon valley insider who knows a thing or two about start-ups and marketing. He’s a general partner with Andreessen Horowitz (and now you know the previous sentence was sarcastic).
In my opinion, this post is the best education you can get on marketplaces and marketplace start-ups. Andrew probably took hours to compile these. I did that in less than 5 minutes… but the content inside will keep you busy for days.