An interesting twist in the world of advertising...
In the episode, the detectives investigate a slaying during a high-school prom.
They use Photosynth, software that stitches together images and creates a three-dimensional map, to re-create the scene of a slaying. In this case, the raw material is cellphone photos taken by students at the dance, which the software uses to build a "synth" of the high-school gym at the time of the crime.
The photographic reconstruction, which receives major airtime in the episode, leads the investigators to a suspect.
Detective Don Flack, played by Eddie Cahill, confronts the suspect with the evidence from Photosynth and then says, "It's Microsoft's world, kid. I'm just living in it."
On a tangentially related note, also see "Microsoft hopes new [free] photo tool will boost Windows" (about Pro Photo Tools, not Photosynth)