texas neuron writes "So Bill Gates reports more than100 million Vista sales prior to the end of December and Steve reports a total OS X market of about 26 million users (19% = 5 million sales). Netapplications reports VISTA market share of 10.48% versus total OS share of 7.3% . The math works out to about 38 million VISTA users online in December. The numbers could be even worst for Microsoft since the October figure of 88 million did not include business volume sales. It is not clear to me if Gates was talking total volume or only retail volume. The percentages are not perfect but it appears that only 1/3rd to 1/2 of VISTA licenses are in use."