2. There's yet another mode to the Shift and 2nd Function/Up keys: tapping the appropriate booster twice locks caps or 2nd (blue) char set respectively. Tapping it again unlocks. And yet another mode, you can hold the booster key while hitting the key you want shifted/2nd functioned. And one more: to get the second function you can hold a key for extended time. Don't release until it turns into the 2nd char on the keycap. e.g. hold down space and a space will appear, but if you keep it held down the space will disappear and be replaced with the @ symbol.

(All my examples are from US version of keyboard, YMMV with other layouts.)

PS, these key functions aren't add-ons that I added so long ago that I forgot doing it, are they? If so, might be nice to post that info here . . .

5. A nice implementation of Gnumeric spreadsheet is available for N900!

Forgot to mention to "power search" here for threads regarding "must have" software "new to n900" recommendations, and favorite apps lists. Lots of advice there, much of it good.