Microsoft Security Essentials has won a lot of praise since its introduction last year. The anti-malware software is unobtrusive and reasonably effective, and its price—free—can't be beat. One fly in the ointment has been the software's licensing terms; MSE is only licensed for home users. Businesses have to look elsewhere for their anti-malware needs.

That's set to change, at least a little, next month. From early October, small businesses—defined here as those with ten PCs or fewer—can use MSE, too. Microsoft claims that enterprise security software is too expensive, complicated, and hard to use for these organizations, hence its decision to expand the reach of MSE.

While it's interesting to see yet another definition of "small business" from Redmond (Small Business Server is good for up to 75 desktops, and the forthcoming cloud-based Small Business Server "Aurora" is for companies with up to 25 users), this is certainly a good move.

Free anti-virus for home users has been around for a long time, but most of the free products include similar restrictions to MSE—if you want to use them on corporate desktops, you have to pay for the privilege. Microsoft's entry into the free anti-virus market was met with mixed reactions by its competitors, with some voicing antitrust concerns even when MSE was a consumer-only product. This foray into the corporate anti-malware market is sure to raise the hackles of the company's competitors once more.