According to one researcher today, those security vendors have little to fear from Microsoft's giveaway. "It won't be the application that puts Symantec or McAfee out of business," said Andrew Storms, the director of security operations at nCircle Network Security. "...Microsoft still has to prove itself in this arena. Take, for example, Windows Defender, which has been free. It's not necessarily the best anti-spyware product available."

Storms also wondered how Microsoft's re-entry into the consumer security space would affect the relationships it's built with antivirus vendors, including those that involve the sharing of threat intelligence. "We've come to learn that Symantec and others have shared their threats and risk information with Microsoft in an effort to better protect all consumers. If Microsoft starts dipping into the market share of these partners, will it affect that intelligence sharing?

The will be available for Windows XP, Vista and Windows 7 as a 4.7MB download from the Microsoft Web site.