Although I agree with @Adrian and many others about the matrix organization, I actually work in a small collaborating environment that use the project-based organization well. We were managed by a manager who reports to the boss. We report directly and remotely to the manager who is from a different organization (the communication was really great because he was really good in replying emails and he always had answers). He organized all the tasks and communicate with the boss. We knew of other projects through team meeting. Though it was true that limited knowledge was shared between teams, our projects were very different and it wasn’t needed. All different teams were great with each other and we actually enjoyed having a specific project to work on in depth rather than being pulled in various directions.