One of the most offensive and disgusting aspects of the modern Internet is multiple ways thief's try to separate you from your money while posing as a trusted company. The most common method this is accomplished is by a email technique called 'phishing.' This is where you are sent a email from a well known company such as your bank or PayPal, and told in this proper looking email that there is problem with your account that requires you to log in to your account to fix it.

The IRS defines phishing as "the act of sending an email to a user falsely claiming to be an established legitimate enterprise in an attempt to scam the user into surrendering private information that will be used for identity theft."

There is a classic phishing email scam involving PayPal here