Tim O'Reilly, he of the animal books (as I like to call them), often posts about how O'Reilly's book sales can be indicative of tech trends in general. Thanks to zealous statistic keeping Tim has a wealth of knowledge about his sales (as as good business man should). The latest trend that Tim has set his sights on is OS adoption, specifically that of Vista/Tiger. Clearly, O'Reilly has sold more Vista related books vs. OS X books (darn marketshare), however, after 6 months Tiger books completely replaced sales of Pather books while XP books are still selling strong (though Vista sales are 50% higher than XP).
What does this tell us? Mac users, at least those that buy tech books, are more likely to upgrade their OS to the latest version while Windows users are taking a wait and see approach with Vista.
How many of you are planning on upgrading to Leopard as soon as it comes out?