At my first job sharing was important business. I worked at a pre-school, my alma mater.
It must be from those summer days on the playground that I gained an appreciation for the sandbox, and for how it has since morphed to facilitate a totally new kind of sharing. Google docs, Open Office, Wikis, and countless more act as valuable labs for learning from and building on one another in the adult world.
(I find also it interesting that, like physical sandboxes, the new ones are not without drama about playing fair.)