A cloud marketplace is an online storefront operated by a cloud service provider.
A cloud marketplace provides customers with access to software applications and services that are built on, integrate with or complement the cloud provider's offerings. A marketplace typically provides customers with native cloud applications and approved apps created by third-party developers. Applications from third-party developers not only help the cloud provider fill niche gaps in its portfolio and meet the needs of more customers, but they also provide the customer with peace of mind by knowing that all purchases from the vendor's marketplace will integrate with each other smoothly.
Examples of cloud marketplaces include:
AWS Marketplace - helps customers find, buy and use software and services that run in the Amazon Elastic Compute Cloud (EC2).
Microsoft Windows Azure Marketplace - an online market for buying and selling Software as a Service (SaaS) applications and research datasets.