Soon after the 10.7.3 update to OS X Lion, people started finding subtle differences in the pointer icons for OS X (hat tip to Daring Fireball). Specifically, the link, grab, copy, and screenshot pointers have all been updated with slightly new iterations for the first time since OS X 10.2, released in 2002.
The link pointer features a slightly angled index finger rather than the traditional straight finger that's been a staple of the icon since even before OS X, and the grab pointer has been updated to more closely match the "Mickey Mouse glove" appearance of the link pointer. The copy pointer features a more pronounced green gradient beneath the "+" symbol. The old pseudo-SLR camera icon for the screenshot pointer, which comes up after hitting Command + Shift + 4 and then tapping the spacebar, has been replaced with an icon that matches the icon for the Image Capture application.
Old icon, new icon, Image Capture app icon
Apple has also updated all icons with high resolution versions for Universal Access purposes, so the pointers no longer look badly pixellated when super-sized via the Universal Access settings in System Preferences.
Beware of comically large pointer
"The simplest explanation is that Apple only just now got around to increasing the resolution of these elements for the benefit of users who use the cursor-zooming Universal Access feature," says Daring Fireball's John Gruber. Indeed, these OS X pointer icons hadn't been updated in nearly ten years. Gruber further speculates that this may be an initial step toward higher resolution "Retina Display" Macs, though he admits that we should "take my conjecture here with a grain of wishful-thinking salt."
Many blogs must have skipped that last sentence, because overnight speculation over possible "Retina Display Macs" has been rampant since the updated pointers gained wider attention. But the simplest explanation that Gruber himself cites is the best one; the pointer icons are a very minor detail in OS X and a feature that remained completely static for close to a decade without anyone noticing or complaining. The updated icons aren't terribly likely to have anything to do with forthcoming updated hardware.