Reamde by Neal Stephenson

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From Wikipedia:

Reamde is a technothriller novel by Neal Stephenson, published in 2011. The story, set in the present day, centers on the plight of a hostage and the ensuing efforts of family and new acquaintances, many of them associated with a fictional MMORPG, to rescue her as her various captors drag her about the globe. Topics covered range from online activities including gold farming and social networking to the criminal methods of the Russian mafia and Islamic terrorists.