John Gruber points out (no pun intended) that the pointer for Mac OS has been changed a high-resolution format. This is in addition to a few other small elements of the interface being enhanced. Gruber also makes note of the fact that when a Mac Mini is plugged in via HDMI, it switches to HiDPI mode sometimes. Altogether, Gruber is hopeful that this means Mac OS is moving towards a retina screen display. Something I could definitely get on board with.
[Source: Daring Fireball]