I have an old account that I hadn't logged into in 6 or 7 months. I was recently able to log into it, because it still had like .0001 BTC in it, because the interface used to only show two decimal places, so I couldn't withdraw everything. One interesting thing is that there was no BTC address associated with it. It looked like a new account that says "click here to make a deposit" instead of showing an address. So I think all data associated with the account really is deleted after the time periods listed. As for being "archived", I wonder what that means, since the account gets archived after all data is deleted. It may just be to preserve the name so someone else doesn't create an account to impersonate an old account.