What exactly is the bank and why is it offline?
There used to be a bank where you could store your minerals, gain interest, etc.
It was taken down because there were bugs being abused, I think.
I'm pretty sure they took it down because it would be unfair to the new members, as the older members could get a crapload of interest, while they wouldn't get that many.
The logic of people who have a ton more money getting a ton more interest was somehow "unfair", so the bank was disabled.