Open Source business models

Open Source as a commercial strategy is interesting – on April 29, I will (depending on travel schedule) participate in a Concours group teleconference on the use of Open Source by large companies. Leading the call will be Jay Williams, and the featured guests will be by William Vass, Vice President, Corporate Software Services, Information Technology, at Sun Microsystems, and Eirik Chambe-Eng, CEO of Trolltech.
Eirik previously participated in a Polytechnic Society meeting I organized on the use of Open Source, and showed a sophisticated understanding of when Open Source works and when it doesn’t. Dan Bricklin, in a recent essay on starting a software company on Open Source, discusses this question as well.
To me it boils down to the depth of the software (what people chose to do with it, meaning to what extent they are locked into it and have an incentive to further develop it,) uncertainty about how it is used (so that there is value to the developing company of having rapid and good feedback from users,) and to what extent you can identify whether the software has been used or not (for instance, Moveable Type can readily identify whether someone has been using their software, as well as the nature of the use; Trolltech can see whether their libraries have been used in commercial software and enforce their license that way.)
My thoughts are not yet well developed on this subject, so I am looking forward to the teleconference. Provided I can make it.