It is the story of a computer programmer named Matthew Sobol. Before the novel begins he is dead from brain cancer. As a brilliant and rich programmer, he left behind some programs to achieve his goals.
Those programs have activated and start off by murdering two of his coworkers and then attacking other people overtly and covertly starts recruiting others.
This is a technothriller - some of the gadgets in there are a few minutes ahead of now, in that sort of technological curve, or perhaps a bit exaggerated, but not necessarily implausible, except perhaps for the overall intelligence of the daemon.
The book isn't perfectly written but it is entertaining. The big problem is that it's anticlimactic - each time it seems like it's reaching the climax of the story, it just kind "blah"s out, and the ending of the novel isn't really an ending, even in that sort of "in real life, there are still loose ends" kind of way - there are no resolved ends, really, other than a tendency to kill off certain characters or to make you think some characters are dead.
So there's a sequel coming out.
I enjoyed the book. I thought it was interesting and thought-provoking. I was seriously cheesed off by the ending, however, and would hesitate to recommend it until the sequel (scheduled for late 2008) comes out.