PayPal has introduced extra security measures which you may now apply to your PayPal account(s), including the free option to have a randomly generated temporary and secondary password (in addition to your normal one) sent to your cell phone before it approves transactions to your account, and the paid option to purchase a security key for $5 which will automatically generate and print the numbers to a small credit-card size device (which they'll mail to you).

http://paypal.com/securitykey

These secondary security measures will make it harder for thieves and malicious hackers to get into your account and fraudulently make purchases using your money!