Paypal is an online service that acts as a virtual online bank. Money can be transferred to other paypal accounts, it can also be used to shop online without giving out your real credit card information. Not all online merchants accept paypal, that is when you will have to give out the real information.
Paypal has come up with a solution to tackle this problem. They have introduced a paypal browser plugin that can generate single use MasterCard numbers which can be used to shop online. This way you can shop on website that do not accept paypal. This keeps your real information secure and you do not have to worry about your credit card being misused. The plugin can also fill in your shipping details and other information required to make online purchases.
It can also track all your purchase receipts, enabling you to track all the online purchases.
Now the bad news is that this feature has only been released in USA as of now. Cant wait for them to release it in India and Philippines. Personally I earn money every month in my Paypal account and prefer to use it for my online shopping rather than use my credit card or withdrawing it to a bank account.