How many times are we going to have to go through this? Computerworld reports that "Windows lost nearly a full percentage point of market share for the second month in a row in December". Except, of course, it's not market share.
In fact, they're "reporting" (I don't think it actually justifies that label) the Net Applications survey of Internet use, which the company itself erroneously describes as "market share". It isn't. It doesn't indicate sales, only a particular kind of usage.
And that's something Net Applications acknowledges itself, in a roundabout way. As it notes on its page on "market share" at present, "the December holiday season strongly favored residential over business usage. This in turn increases the relative usage share of Mac, Firefox, Safari and other products that have relatively high residential usage."
That's the important word, here: usage. And usage doesn't tell you much about the number of machines being sold, or the installed base. So to draw out a headline which makes it sound like the sales of Windows machines are on the wane, as Computerworld does, is either hype or sloppy journalism.
UPDATE: TUAW gets on the same bandwagon, with the same dumb headline and opening line. Look, I know that an Apple blog is going to want to say that Mac market share is "almost 10%", but reporting this without the caveat that it's not really market share AND ignoring NetApplications own warning about Windows being under-reported is either consumate spin or stupidity. Are reporters no longer supposed to look at things like this critically?