Back when it was announced that Blizzard was going to open up community API data streams for enterprising coders, developers, and site admins, we speculated on some of the cool features a system like this could bring. This was well before transmogrification was even a possibility in our eyes, and it looks like the API is being taken to another level.
For those of you who don't know what an API is, imagine that it's like a special set of codes and syntax that you can plug in, ask Blizzard's servers directly for an answer, and receive data back in a specified way. You can then use that data to display cool information -- for instance, someone's transmogged armor set.
Blizzard's API team has really outdone itself with these cool data streams, as have the developers out there who took this information and ran with it. I can only hope and imagine all of the cool things this information can help product that are still just ideas in WoW players' heads.