ChoiceTree consists of two components: the Windows
desktop "ChoiceTree Writer" and it's companion, the
low-cost "ChoiceTree Reader" for Palm OS and
PocketPC handheld computers.
(One Reader license comes with purchase of the Writer.
Other Reader licenses available separately.)
Using the "Writer", you create decision trees on various subjects of interest to you, then install the trees onto your handheld computer (running the "Reader") for your own use, or distribute or sell them to others who have use for them on their own Reader-equiped handheld.
Everybody has seen decision trees, in which you make a series of choices before arriving at a final set of instructions on what to do in the situation your decisions have described.