Paypal allows you to transfer money to your friends and family. To do so, you just need the email or phone number of the recipient. I just did this and noticed something interesting: I just gave the email address of the recipient, but in the list of transactions, paypal shows the full real name of my friend as recipient, and also sent me a mail that contains the full name. This means, you can easily find out the real name assigned to some mail address that is used as a paypal account by just sending a cent to the address. Of course the recipient will notice it, but probably will not complain.

This is especially interesting as paypal itself says in the footer of every email that scam mails will usually not include your real name. But scammers could first send you a cent to find out your real name and then greet you with your real name in the scam mail.

It seems to be a good idea to use an email address for paypal that you use nowhere else. This way, it is not possible to find out your real name through your normal mail address. Additionally, this has the advantage that you can ignore any phishing mail that you receive in the name of paypal, but through your normal mail address and not your paypal mail address.