For years, Phelps writes, Microsoft protected itself through a clause called NAP -- Non-Assertion of Patents -- which it forced upon business partners.
NAP freed Microsoft from worrying about most patent claims, he notes, but not from trolls who were not business partners. Worse, it left Microsoft isolated, with great ideas left as mine tailings behind the shop.
The Phelps plan was to sign cross-licenses with business partners instead, to aggressively patent what it had, and then to license those patents to start-ups.
The cross-licenses would let Microsoft do business with partners in a similar way to the old days, while the patenting and licensing of new inventions would spin straw into gold for new entrepreneurs, who might then become business partners.
In Phelps' view it worked a treat. And it's hard to argue with the financial numbers the company has put up the last five years, while losing not only CEO Bill Gates but his entire founding generation.