Azure marketplace is the online market place for developers to share, find, buy and sell building block components, trainings, services etc. Marketplace consists of Data Market & App Market.

Data Market(Dallas): It includes data, images and web services from different data providers and from public source. It also includes the visualizations and analytics to represent the data in more meaningful way. For more details https://datamarket.azure.com/

App Market: It consists of trainings, services, finished applications, etc. It also includes various tools for developer & administrators. For more details http://windowsazure.pinpoint.microsoft.com/en-US/Default.aspx