The following message is a hoax. It's designed to get users to forward copies to as many people as possible.  Users are often taken in by the message and send out as many copies as possible to everyone they know, only to find out they have unwittingly participated in the hoax themselves.  The subject is often similar to:

$800 From Microsoft!

The body of the message is often similar to:

Netscape and AOL have recently merged to form the largest internet company in the world. In an effort to remain at pace with this giant, Microsoft has introduced a new email tracking system as a way to keep Internet Explorer as the most popular browser on the market. This email is a beta test of the new software and Microsoft has generously offered to compensate who participate in the testing process. For each person you send this email to, you will be given $5. For every person they give it to, you will be given an additional $3. For every person they send it to you will receive $1. Microsoft will tally all the emails produced under your name over a two Week period and then email you with more instructions. This beta test is only for Microsoft Windows users because the email tracking device that contacts Microsoft is embedded into the code of Windows 95 and 98. I know you guys hate forwards. But I started this a month ago because I Was very short on cash. A week ago I got an email from Microsoft asking me For my address. I gave it to them and yesterday I got a check the mail for $800. It really works. I wanted you to get a piece of the action. You won't regret it.

There are many variations of this hoax in particular the amounts discussed, the names and phone numbers, and the percentages often change from one mail message to another.  If you receive this message please simply delete it.