When Microsoft announced Windows Live OneCare almost five years ago, Symantec, McAfee, and other consumer-oriented security vendors reacted with vigor, attacking Microsoft for intruding on their ground. They then set out to mimic OneCare with products such as Norton 360 and McAfee Family Protection.

Ultimately, those products were quite successful, Microsoft never gained past single digital market share, while Symantec finished 2008 strong with 22 percent of the market, compared to 10.9 percent for McAfee. This in turn made Microsoft change course. So at the end of last year, Microsoft announced that it would discontinue OneCare in 2008 and launch a free anti-malware product code-named “Morro” (now known as Microsoft Security Essentials).

Microsoft recently made Microsoft Security Essentials (MSE) available as a limited public beta, and so far, the product has been tremendous. Currently users of the product have reported that MSE is small, light, fast and doesn’t bog down PCs like the top-heavy suites offered by Symantec and McAfee. Best of all, MSE will be free. How well do you think Symantec and McAfee will respond?

According to Symantec, the real issue is that most infections occur online now via so called drive-by downloads, typically via a web browser. (Microsoft’s Internet Explorer 7 and 8 already both protect against such attacks) But as is always the case, Windows users should look past the marketing bluster. While most PCs come with free trial versions of security products from Symantec, McAfee, and others, users of those products rarely upgrade them to full versions or keep their subscription activated.