Have had my n900 for about 1year and 4months and just found a small thing about my n900 that i didnt know before but I think is very helpful, in fact its possible that it has been introduced in a recent update and i was not aware.

Basically at times i have found using the blue shift key on the keyboard to type one of the blue characters a bit awkward or even annoying... lets say if you want to type * instead of trying to hold the blue shift and press A or press blue shift twice, try to hold down the A key for just over 1 second and voila no need to use the blue shift key.

This applies to all blue characters.