Chrome was introduced almost 18 months ago, but yet it has already become the third most popular browser in the world. NetApplications' figures cover the entire month of December 2009, and they show that Google Chrome has gained 0.7 of a percentage point, putting it at 4.63%, ahead of Safari's 4.46%. Internet Explorer lost almost a full percentage point, dropping to 62.69%. Firefox remained more or less flat at 24.61%, while both Safari and Opera gained slightly.
Chrome's steep rise in December can probably be attributed to the release of the betas for Linux and Mac OS X, so we may see a slight decline again in January, as some people will most certainly fall back upon their established choice of browser.
As for operating systems, Windows 7 is, unsurprisingly, doing rather well. Microsoft's latest baby already broke the 5% mark, and in December its share amounted to 5.17%, up from November's 4%. Windows 7's popularity seems to have little effect on Mac and Linux users, as both platforms remained more or less flat at 5.11% and 1.02% respectively. Since both Windows XP and Vista lost share, the logical conclusion is that Windows 7 is competing with previous versions of Windows. That really shouldn't surprise anyone.
Of course, the usual disclaimers apply. These are statistics, and therefore, are troublesome. However, even though you shouldn't take them at face value, they can be used to indicate trends. In this case, the two important trends are that Windows 7 is eating away quite well at the base of previous Windows versions, and that Chrome's star continues to rise.
As always, do with it as you please.