I would also recommend if you have time, a companion book,
Dataclysm. It is more evidence based, where
Modern Romance is more anecdotal.
http://dataclysm.org/
Full of wit, insight, and colorful graphics—and written by a true industry insider—Dataclysm reveals and explains how people flirt, fight, love, and hate through Facebook, Google, OkCupid, and Twitter.