It is an amazing piece of software. Very empowering.
Search youtube for "sketchy physics" or "sketchup animation" to get an idea of its full capabilaties. It is pretty much only limited by your hardware. I only use it in a very simple way.
Other people are using it for
art and animation, for engineering, for landscape design, for decorating, you name it.
The free version has most of the features of the expensive pro version but with the pro you can export to CAD, print 3d models and use the data in other useful ways.
Some of the features that I think are really cool;
You can add dimension lines to a pic and create a 3D model out of a photograph.
You can import textures and colors from pics and other sources.
With the sketchy physics add on you can make wheels that turn, and gears that move and such.
You can make a
video walkthrough or flyover of a model.
The ability to make accurate 3D topography. (still figuring this one out, but I think it could be a real asset for a
permaculture designer trying to explain
water management.)
access to the 3D warehouse where you can find millions of other people's drawings to import into your design. For example, the florescent light fixtures in my drawing were imported from the warehouse and took me all of 30 seconds to add to the model.
Sometimes I wonder if I can trust Google with my info, as they are starting to look more like big brother every day. But things like this I feel reveal a philosophy of empowering people vs. subjugating them. Makes it easier to live with the fact that they already know everything about me.