We have been reevaluating our cloud service, and how free users interact with it. We disabled new sign-ups as we go through this exercise.
If someone with a paid account invites you to their site to collaborate, then you will get a sign up. Otherwise, you need to work with Alfresco Sales to get an account.
Is there any indication as to what the plan is for free networks in general, and how existing free networks (e.g. networks used by companies who aren't enterprise customers) will be handled in the future? Does part of the cloud element come under your brief as the product management for the community edition or is it considered completely separate?
Another Product Manager is responsible for the future of Alfresco in the Cloud. I haven't taken the time to follow it very closely, but have been told that we are contacting owners of free accounts on the service.