One of the arguments used against linux and open source in the past by large proprietary OS vendors with significant market share is that of course there are fewer reported security issues with linux when compared with the tsunami of issues with their products because the linux install base is so small... Well linux based server systems now run most of the internet so that statement no longer holds water, and yet the linux and open source community are still better at detecting and correcting security issues than proprietary equivalents. This article by Jack Wallen on TechRepublic outlines some reasons why.