A lovely information leak on Paypal's front-page is if you attempt to login with a banned account, and any password whatsoever, it gives you a nice error message saying that account is banned (therefore confirming the account exists, info leak #1) and also gives the current account balance (info leak #2).

I know this because my account is banned.

Why's my account banned? Because in 2006 I received an unsolicited phone call from somewhere in Nebraska claiming to be Paypal and informing me they needed to verify my account credentials. I played along with the obvious phishing attempt for a few minutes until they demanded the email and mailing address on my account to "verify I was the account holder". I told the woman on the other end to go fuck herself and hung up. Turns out it was Paypal and they banned me for failing account verification.

Fuck Paypal.