High Quality Content by WIKIPEDIA articles! Microsoft SpyNet is the network of Windows Defender and Microsoft Security Essentials users that help determine which programs are classified as spyware. The signatures created for any submitted programs by the users of the product are available to all users, displayed as a bar graph that shows the percentage of people who have allowed, blocked, or removed an item. This method of spyware classification allows rare, unknown, or new spyware to be categorized as most people choose to send their data.