Link - ArcGIS Engine Licensing
I was in the same boat as Bill, a long time MapObjects programmer who was **very** comfortable with the MO deployment and licensing. We’ve just started migrating to Engine from MO 2.3 so we too are still learning about how exactly this all works. I spent some time down at the Embedded Island at the 2005 ESRI User Conference and I think I’m now on board with the licensing, but there should be a document outlining the changes for MO programmers moving to Engine. Bill has some ideas about the way developers buy deployment licenses that might help MO programmers, but I just don’t see them changing it from the current method.
Essentially, ESRI needs to come up with a model that allows the developer to purchase runtime deployment licenses from ESRI and then be able to distribute them to his/her end users based on whatever cost-recovery model (if any) the developer chooses. I can envision an automated tool that interacts with the ESRI web site. Such a tool could facilitate the purchase of the right to generate a certain number of runtime deployment licenses. The tool could then decrement the number of licenses each time the developer actually generates a key. When the number reaches zero, the developer has to buy more licenses from ESRI.