The Roadmap serves primarily as a communication vehicle; providing our internal and external stakeholders with insight into the long term goals and priorities of the project. This involves management of the larger scale enhancements which the community has deemed the most valuable to the product.
It is important to note that when submitting enhancement suggestions you need to put yourself in the Product Management role and provide a thorough explanation of why you feel your enhancement is important and who will benefit from its adoption. Ultimately you need to convince the community that your enhancement is one of the highest priority features for the platform - so put on your sales hat and roll up your sleeves!
The Roadmap also provides the ability for community members to Vote for enhancements and provide feedback in the form of Comments. Integration of the most highly requested features into the product still depends on the usual constraints including scope, scheduling, resources, risk, etc... however the communication received through this channel is invaluable to shaping the future of DotNetNuke!