rticle gives suggestions on how to set up your Mozilla application for extension development. Unless otherwise specified, those suggestions apply to both Firefox and Thunderbird as well as SeaMonkey version 2.0 and above.
Why it is not replaced by COM, how it works, network DDE, links to other sources of information. DDE is support is being removed from Windows (Windows 7 x64 seems to have an issue with it)
Understanding Beyond Your Textbook. Articles on a variety of topics that really explain complicated subjects in a way that anyone can easily understand.
M. Marschollek, K. Wolf, O. Bott, M. Geisler, M. Plischke, W. Ludwig, A. Hornberger, and R. Haux. Proceedings of the 12th World Congress on Health (Medical) Informatics
-- Building Sustainable Health Systems. MEDINFO2007, 20.-24.08.2007,
Brisbane, Australia, volume 129 of Stud Health Technol Inform, page 8--12. Amsterdam, IOS Press, (August 2007)
E. Schwarzkopf, M. Bauer, and D. Dengler. Proceedings of the 7th international conference on Intelligent user interfaces, page 220--221. New York, NY, USA, ACM, (2002)
E. Schwarzkopf, M. Bauer, and D. Dengler. Proceedings of the 8th international conference on Intelligent user interfaces, page 287--289. New York, NY, USA, ACM, (2003)