We hope to start inviting early adopters in in March to do final tweaking and load testing. We'll probably go to beta invites as soon as we think it's stable and useful. From there, it goes where the users take us!
Right now the only way to be considered for early access is to fill out our feedback form: https://docs.google.com/forms/d/1pGhxa1NvBmqVvV4tPt0YTiUcDRx...