Keyhole

Google acquired Keyhole (a satellite imagery provider) about 6 months ago.  Now Google Maps, the cool "click and drag" AJAX-based map application that so outdid MapQuest, has integrated that data with exceedingly cool results.  For example,

http://maps.google.com/maps?ll=38.514850,-122.788134&spn=0.021372,0.032701&z=2&t=k&hl=en

Just toggle back and forth using the "Maps" and "Satellite" links in the upper right corner.

I got word of this when a pal of mine who's a Googler wrote me about it, and I see that Yahoo! News picked it up about 2 hours ago.

Very, very cool.

Update: Kottke makes a good point: the reason that Google Maps is cool is about the interaction, not the underlying technology (all of which has been around for a while).  Basically, good tools tend to obey the DWIM (Do What I Mean) principle.  It was a feature of Chessmaster 2000, where you could pick up 3D pieces (hey! this was back in 1986!!) and move them around, instead of typing "e2-e4" (i.e. board coordinates, like Sargon did).

Of course, some times it takes financial muscle to pull all the bits together for a great interaction.  Google Maps almost certainly couldn't have been done by two guys in a garage.