One thing you must understand is no matter how much security is programmed into a web-site it can be hacked. Hacking a web-site is like robbing a bank, many can do it but few get away with it. But on the security issue Paypal is secure because it uses the https protocol which is suppose to encrypt the information while in that url scheme completely. When you make your transfer so the information should be encrypted. Unless someone is specifically targeting you, you shouldnt have to worry about Paypal security. Also dont make your password too easy because if your password is common more than likely it'll be included in a wordlist for dictionary attacks and you might just get sniffed out. The only other thing you have to worry about is packet sniffing. If some one is sniffing out your packets they can get the information needed to get your password which is fairly simple. But it cant be done by anyone, packet sniffing being effective like this usually has to be done by someone on your same network so I wouldnt worry about it. Excuse me if my explination has some errors or it's a bit wrong, I havent been into the whole "security" scene for some time now lol. Too busy trying to grow weed xD.