Basically it's an easy to use, rapid 3D program that lets you sketch out ideas much like you would on a piece of paper. I used it to mock up my garden in about 30 minutes and my friend Michael did his entire house. The one downside to it was that until now it was really expensive, like around $500 per license. When Google announced they bought the app earlier this year, my one wish was that it would someday be free and it looks like that day has come. Sweet, though the free version is Windows only at the moment, which is odd since the app works great on OSX and I assume it's coming very soon for the mac.