Mac SHARE GREW AFTER WINDOWS 7 DEBUT..

If Microsoft (MSFT) was hoping that the launch of Windows 7 would halt the erosion of its operating system market share — and curb further inroads by Apple (AAPL)  — there is no evidence that it's working yet.

In fact, preliminary data released overnight Sunday by Net Applications show Mac OS X's Internet share growing by 2.73% in October, from 5.12% to 5.26%.

Windows' Internet presence, meanwhile, fell from 92.77% to 92.54% — its ninth loss in 12 months. Windows 7's share, however, was more than 2% even before its Oct. 22 general release, thanks to widespread use of early release versions. By Oct. 30 the Windows 7 portion was 2.85%, largely at the expense of Windows XP, according to a separate Net Applications report.

Net Applications, it must be noted, is not measuring share of market in the sense of sales revenue or unit sales. Rather it tracks the presence of various operating systems on the Internet by sampling browser data from visits to its clients websites — some 160 million hits per month. It's a methodology that tends to favor devices that make it easy to navigate the Web, which explains the relatively high "market share" of the iPhone in the firm's monthly surveys.

You can see Net Applications' October report here. The results are summarized in the chart below.

Source: Net Applications