Primarily as a developer, I always wanted an online service which is free for me to put my projects under source control. I could find few paid TFS hosted services but I was not ready to put sample projects or source code which has no real dollar value associated under a paid service.
Secondly, I used to give sessions on TFS & source control and main problem for my students was to perform hands on practice when they are not at the lab. I used few alternatives like CodePlex by using community projects, VPC and Handson Lab environment at MSDN etc. but all those were/are still workarounds.
Lastly, deploying & implementing TFS is a relatively big effort for companies who want to 'test the water' first before diving deep. It sometimes becomes a real challenge to coordinate TFS implementation and promote usage among teams without a 'test' or 'dogfood' environment.
Team Foundation Service: TFS as a service by Microsoft at http://www.tfspreview.com
This is a positive step towards developer empowerment. Specially - this will be helpful for all small, medium and large enterprises where developers and IT teams struggle to set the working environment for learning TFS and source control practices. Also not only this, it will be a boost for all freelance developers who struggle to maintain source control for their code & delivery while keeping the cost to the client low.
While the service is in preview mode, the feature-set is still very rich and most importantly users can get started for free. The website has a mention that when the service is out of preview mode, the free services will still continue(* - may have reduced functionality or may be not) and there will be paid services as well. I sincerely hope Microsoft will continue to offer free services at least for Source Control and Continuous Bulds.
The website also has a menu named "learn" and the content are amazing. It is mostly step-by-step and easy to understand and practice. Here is a direct link for 'Learn":