In the text of the message it then states "Your mailbox has exceeded the storage limit which is 20GB as set by Your administrator, you are currently running on 20.9GB, you may not be able to send or receive new mail until you re-validate your mailbox. To re-validate your mailbox please Click "website link". Thanks, Mail Server Administrator."
When you click on the website link (which I have removed for your safety), you're taken to a very legitimate looking screen like the one below, which some of you may have seen if you've ever used Microsoft's Outlook Web Access feature. But in this case, it's a fake Outlook Web Access page designed solely to steal your email address and password, should you be too busy to realize what is really happening and enter that information (Note: DON'T DO IT!!!).
There was a similar scam message recently linked to the AOL account of a well known local real estate agent and several of my clients did in fact enter their email addresses and passwords when prompted to do so. Just to be perfectly clear, NEVER EVER NEVER give up your email address and password to any website you open from a link inside another email. It is very easy to design fake web pages and fake website links and their sole purpose is to steal access to your account and use it to send out spam or to read and pilfer the personal contents of your emails. That would definitely make for a not-so-happy Halloween!
Want a safe demonstration of how easy it is to design a website link that goes somewhere completely different than where it claims, then click here: http://www.facebook.com