it downloads shit the the demo requires (engine, etc) and leaves out stuff you won't need (maps and models not used in demo, etc) then if you choose to buy it down the line it's quicker to download :3
Yeah merchuke is right. Also dont this steam works this way, but shareware titles have (usually) all the content you need. However most of it is block by a passcode or serial key.
I'm doing good, just made my first drink of the day, so better now, Captain and Coke today. I had to cut grass all day, then get my hair cut. I messed with my wifey, she knew I was going to get hair cut, and I went and bought a purple dyed wig, and came home wearing it, she freaked out, thinking I dyed my hair purple, was funny.