In an interview we did at Enterprise 2.0, Christian Finn said Microsoft will offer the marketplace for vendors who want to sell their products through the Sharepoint platform.

"We will have a route to market for vendors who want to have applications and add-ons available," Finn said.

Conceptually, Finn said, you think about a marketplace idea. Customers will navigate from the Sharepoint interface to see what web parts are available for a trial period.

Finn said that from their perspective, collaboration is mostly on-premise. Customers are starting to move to the cloud. "We are seeing early customers starting to move. When we see that bell curve adoption we will definitely be there."

But collaboration services are increasingly cloud-based. MindTouch, SocialCast, Socialtext and a host of other companies are offering best-of-breed-services.

The availability of a marketplace brings up a lot of questions about the role that partners will play with Sharepoint. But it also raises interesting competitive questions about the role of Sharepoint as a cloud-based service. It almost looks like it will be more of a Software-as-a-Servce (SaaS) than the on-premise platform it is today.

The Sharepoint application marketplace will evolve out of The Gallery, a resource within Sharepoint 2010 that serves as a central place for templates. Microsoft will initially offer their own web parts through Gallery. Eventually the service will take a different name and migrate to offering partner services.

We asked Finn what the model will look like. Will it be pay per use? How will the application marketplace be administered? Finn said most of the details are being worked out in Redmond.

The service will have IT safeguards. Finn said that IT managers will have a level of control over what applications users may integrate.

What Finn describes sounds similar to application platforms now commercially available. Salesfoce.com is the obvious example. TheirForce.com platform is a full development environment. AppExchange is the platform for building third party applications on Salesforce.com CRM.

Dazzle from Citrix also comes to mind. It is an iTunes like service that is all about making IT more consumer friendly. Employees may choose the applications that they want to purchase. The service is set up as a store front that can automatically stream the application on a virtual desktop to a Windows PC, a Mac or an iPhone.

Details are few about the application marketplace that will be offered through Sharepoint. But it does point to the increasing significance of third-party applications for the Sharepoint platform and how the service may evolve as cloud computing becomes more prevalent.