As some have mentioned earlier a way to auto reset a certan date would be usefull. Also a log function wolg be good. Now to the big downside, the counter gets crasy after 2,somthing gigs and starts to count backwords. This is not good! I use 2-5gigs GPRS data every month.
A good app, it can be alot better with some improvment.

just filed a bug https://bugs.maemo.org/show_bug.cgi?id=9875 or let's say a feature request to implement a user selectable offset.
could be useful you travel abroad and you have to change the SIM or for any other reason why the counter could get out of sync with the real traffic. home it was the right place to place the request.