So I was thinking about something like the notes that we use, posting them as if they would be post-its on a space determined by you (or TS)...
Maybe optional notes: different colors, private or public...
Maybe we could write many things.. For example our testimony: "this person is indeed a very nice person" or some shopping list, as those on the refrigerator door: "don't forget to buy - milk, eggs, meat, cherries...", or simply some message: "hey you, I was here". It would be cool to be able to draw on the papers, but i guess that it could make the things much harder for the developers.
Brainstorm a bit. Improve this idea.