Problem at hand: How to present two large hierarchies in Web UI for computer-illiterate users that fill some kind of boring application form.
Use-case: User selects item "a" from hierarchy "A", then it selects item "b" from the (completely unrelated) hierarchy "B" and fills in a short free-form text to supplement his choice.
Both hierarchies have less than 10 levels in depth (usually - 5), but each level could be very wide (20,40,50,100 items).
So, drawing the whole "tree" and allowing user to "click it" is out of question. Gradual descent through the tree is possible, but: 1)there could be case with a user being lost/unsure where to navirate -> he would be forced to backtrack through different branches until he found what he is looking for 2)there is an issue with "wide subtrees" - they could be too wide to present them in one line or column on the screen.
Computer-literate users could be saved by the incremental search that would dynamically trim the tree (provided that UI would be speedy enough during the process).
Right now I'm struggling with users who are reluctant to abandon the mouse and press some keys.
Any ideas for me?