[finnh]

I think the line here is pretty straightforward: the contents of your mind are all yours. Anything beyond that (documents, source code, lists of prospects) is not.

Non-compete clauses will try to limit the usefulness of the "in your mind" knowledge by restricting the domains in which you can work post-departure. It's my understanding that such clauses are generally held to be unenforceable except in an acquisition scenario.