Rule 34, by Charles Stross
This is a sequel to Stross's earlier Halting State, although you don't need to be familiar with the earlier work to make sense of this one.
It's a page-turner alright, filled with believable characters having an awful time for our entertainment, and the text sizzles with humour. You'll have to be a geek to understand all the little jokes, but that's not a pre-requisite for enjoying the book, you'll just get more out of it if you're from the right background.
Unconditionally recommended for all but the most puritan of agèd aunts, as it gets a bit nasty at times.