I've split it up into multiple pages: the first page classifies you as an active or inactive user and then sends you to a detailed questionnaire on how you use it if you are active, or simply why you stopped if inactive, and then both go to a long demographics/background page.
Sounds good. I would also add a "never used it" option. It can go straight to the demographics/background page. Otherwise you might have people who never used it classify themselves as "inactive user".
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.