It's only been about a week since the Salesforce.com acquisition closed and digital marketing services company ExactTarget is already busy with new projects. The latest is called the HubExchange app marketplace. The platform aims to help marketers install third-party apps into ExactTarget's Interactive Marketing Hub, in a move to help bring their data together into one location. The HubExchange gives marketers access to and the ability to integrate with apps built by ExactTarget and its global ecosystem of technology providers. At launch, the exchange has more than 50 apps available.