The most famous example of noncompete agreements in the US was the one that saw Apple, Google, Intel and Adobe agree to avoid recruiting from each other - until it was found to be illegal and fines were issued all around.

In this piece from HR Executive, Peter Capelli of Wharton provides a short summary of the rules and gives a view as to why noncompete agreements are so much more common than ones involving price-fixing - despite the obvious similarities.