When people think about classical marketplace model, they think about ebay, Amazon marketplace, where there is natural supply & demand & transaction.
Nowadays the marketplace model is expanding into different areas: exchange of information, goods/services, money, and the definition of transaction/interaction and the way to monetization has changed as well. There also comes many hybrid type of marketplaces where marketplace is combined with SaaS, or marketplace is become part of product feature (the goal of marketplace changes) etc.
What are some interesting marketplace models you see? How are they different from classical marketplace model?