Web businesses such as eBay®, Amazon® and a whole lot of others have long seized to be mere websites; they have morphed into web business platforms on the "cloud". By adopting a platform strategy, they are building an ecosystem of developers, partners and entrepreneurs to build innovative applications for customers. As platform owners, catering to his heterogeneous ecosystem is a huge engineering challenge in itself. This session, we would discuss some of these challenges along with some recipes to overcome them.