Interestingly, the Builder and the ActiveProject Server communicate using Distributed Common Object Model. There are several types of users allowed on the system, and user information is maintained separately in each of the project databases, which access control granular to individual tabs. Globally, administrators can add users to the system, allocate user licenses, create new projects and use the ActiveProject Builder. Creators can run the Builder to change projects. Users, called publishers, can post new data to an existing project via a Web interface.
Reviewers can look at data and post comments.
Viewers can look at the data and comments but can't post anything. Publishers and reviewers can also subscribe to particular project pages, and they'll be notified via e-mail whenever those pages change. Each type of user, except for the viewer, requires an ActiveProject license. The way the software is structured, software licenses are allocated per user per project. So, if you're a general contractor working on five different major projects for different clients, and you want all 25 of your employees to have full access to each of those projects, you'll be using 125 licenses.