Well, the world doesn't end but permanently changes due to a computer daemon (though there is a lot of death involved). "
Daemon" and "
Freedom TM" by Daniel Suarez are about a computer program set loose on the world after a Bill Gates/Steve Jobs type character dies.
I found myself freaking out about a computer program changing my world, then I rooted for it then I freaked out again. I was all over the map in how I felt about the program. I found them techy, geeky, fun, scary and thought provoking.