Thanks for the encouraging words James.
We are not only aware of Project Pier (PP), but in contact with them.
OpenGoo was not conceived as an ActiveCollab fork. We make use of ActiveCollab as we use FCKEditor, TrimSpreadsheets, S5, and would use any other Open Source project that could help us make OpenGoo better, with the least effort.
We are concerned about the uncertainty of AC's future license model, as the PP team is. But I would rather join forces with PP than make another AC fork (Marcos already stated that on another post). This means we could probably use PP (or part of it) as our main framework, instead of AC. But OpenGoo and PP have a different set of goals. Hopefully some sort of collaboration among the two projects will be achieved.
Good luck with your RailsCollab project, and keep us informed of your progress.