As charted by GoSquared based on all the pageviews across all the sites they are tracking analytics for.
Here on shawnblanc.net — which has a decidedly more Mac-nerdy audience — Mavericks is already the dominant desktop OS, representing 21-percent of today’s total pageviews so far.
Here’s the breakdown for my site so far today:
|Operating System||Percent of Pageviews|
|iOS 7 (iPhone + iPad)||33%|