Apple's OS X Mountain Lion now powers more than 10% of all Macs, and may be on the way to outdoing its predecessor, Lion, in adoption speed, an online advertising network said today.
Chitika, which mines its ad impression data for trends in operating system and browser usage, said Thursday that as of Aug. 27, Mountain Lion accounted for 10.3% of all versions of Apple's operating system, with an almost-equal amount of its gain coming from the last two editions.
Apple launched Mountain Lion on the Mac App Store just over five weeks ago.
OS X 10.6, aka Snow Leopard, retained the top spot in Chitika's ranking with a 43.3% share during the week of Aug. 20-27, down more than two percentage points since the end of July, while Lion, or version 10.7, accounted for 31.5%, off more than three points.
That week's Mountain Lion average was 9.6%.
Chitika said Mountain Lion was on pace to out-perform Lion's climb last year. The 2011 upgrade took approximately three months to reach the 14% mark in the company's measurements.
"Mountain Lion received widely positive reviews by critics upon release, namely for its vast array of new features which made it feel like a genuine upgrade," said Chitika in a blog post Thursday. "On the other hand, Lion was criticized by many prominent bloggers for its lack of innovation and behaving too much like iOS."
Just two days after Mountain Lion's launch, Chitika had said the new operating system's share of all Macs was an impressive 3%.
Net Applications, another source of operating system usage, has yet to publish its data for August -- it will do that early Saturday -- but according to its most recent numbers, Mountain Lion powered approximately 4% of all Macs at the end of July, a good-but-not-great showing compared to Lion's 5.5% the year before.
The difference between Lion's and Mountain Lion's uptake in Net Applications' measurements could be due to Lion shipping five days before Mountain Lion on the calendar. OS X Lion launched July 20, 2011, giving it 12 days during the month to accumulate share, five more than Mountain Lion this year.
Mountain Lion is available for $19.99 through the Mac App Store, where it remains at the top of the bestseller chart for paid software.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.