An excellent footnote in The Global Minotour. From loc 3865:
Once all your music, films, applications, addresses, etc. are on iTunes and readily accessible by any Apple product (iPod, iPhone, iPad, etc.), the opportunity cost of buying a Nokia or a Sony device is huge (even if these companies bring a better device to market) –you need to spend literally hours setting the new gadget up. Thus, iTunes gave Apple immense monopoly power, of the same type that Edison and Westinghouse were trying to create for themselves.