The Forum is where innovators can ask sponsors questions directly regarding the challenge, discuss the general subject area or even bounce ideas off each other. A lively Forum is a good indication that people are interested in a particular crowdsourcing project.
As a sponsor, it's very important to monitor your Forum daily and respond to comments or questions in a timely manner. This builds trust with the community that the challenge is legitimate and you are concerned with ensuring its success.
As an innovator, this is where you will want to ask specific questions about the judging criteria or guidelines and possible find other users to form a team with. Finding a team or recruiting additional team members can also be done within the Team Matching feature. You can view where to locate and how to use the Team Matching here.