Franny, yes everyone shares so much there.  All of the wallpapers and backgrounds I have posted to the public I share with anyone that drops by as well as I let the members of the Design group know when I put up another album (each album has about 100 hi res wallpaper/backgrounds in each.) I'm a background addict.  lol

 

And the theme groups have the premade theme codes and all the images included for those.  Here, I think you have websets which you use html.  And there we have themes that come with CSS code that you install if you don't want to design your own.   We have tons of theme groups too but the largest one is linked to the Multiply base theme option.

 

So you can do anything you want with your personal site or group there as far as design goes.  You will rarely ever find two sites that look alike with ten million plus users there.