Vic Gee, author of the Mind Mapping Blog, envisions a day when there is total interoperability of mind mapping programs. In other words, any program can open and work with files created in any other program. As a first step in this quest, he has created a fascinating visualization that depicts which programs can "talk to" the two mind mapping applications with the greatest number of users, MindManager and FreeMind. This detailed diagram is interactive, with buttons that lead to further information on each program when clicked. Vic has supplemented this rich visual repository with information on other visual mapping programs that don't connect with these two market leaders.
If you notice any missing information, please let Vic know, so he can continue to improve upon and expand this visual model.