One thing I really find annoying in Collabtive is the use of the name as the username used to log in. I really doesn't like this as one would want to have the real name of the people working in a project, but this complicates the login procedure having to write the full name specified in the Name attribute.
Why not just add a 'username' attribute like just about every other system in the whole world? (or taking the other side's approach a 'Name' attribute that doesn't relate to the login procedure but has the full name of the person/company/area/etc.)
