"Daemon" and "Freedom" by Daniel Saurez. Very enjoyable reads, and chock full of not-too-distant futurism. They display an enormous amount of thinking about how social networks and the massively increased availability of data about our lives are changing the ways we interact with each other. Sprinkle in mysteries that play out in both reality and MMORPGs, lots of interesting devices, and a terrifying peek at what a technology-driven global economic meltdown could look like, and you have the basis for these books.