Some more thoughts...
1. It's hard to motivate yourself to input lots of data into a spreadsheet, even when you're following a personal whim.
2. The search function should have 4 filters - timeline, place and two other variables (context sensitive)
3. 3 (three) moveable sliders, floating on the map, with category buttons along the bottom. Needs to have the potential to be trimmed down to a iphone/android screen - perhaps have 2 views, one with 4 sliders taking up the whole screen, one of which is some kind of strange mobius strip type map of the world...
4. What are the categories? Define by nature of output - i.e. "Writing", with 'literature; poetry; science' etc as sub-categories? "Audio", with 'music; spoken word; nature'? It should be intuitive but also prompt thought, encourage connections, argument, refining.
5. Moderation - can we build this into the way in which users comment, express support/disagreement? I like the idea of having all dissenting opinions displayed, but proportionate to the support they have (i.e. consensus position covers most of the screen, all others squished to the sides). Difficult cases - holocaust deniers? More difficult cases - majority opinion becomes something manifestly untrue (according to me and other people I like) - how to encourage a continuing skeptical examination?
To iPad or not to iPad - discuss.