I read this article about how Ebay and Paypal are working to try and cut down on fake emails. They are currently working with Yahoo using their anti-phising technology to try and block fake emails by validating the sender with a digital signature. The emails they are targeting are the ones that look exactly like an email from Paypal or Ebay but if you click on the link you are directed to a completely different website that looks the same. They are designed to fool you into entering your user name and password into their fake site, thus compromising your account. Personally I never click on a link from any email that looks like its come from Paypal or Ebay. Instead I tend to log into my account, if there are any issues that need my attention I will have received a notification about them. However, 99% of the emails are spam.