Existence by David Brin is a beautiful explosion of ideas. I enjoyed it very much. The style most reminds me of Stand on Zanzibar by John Brunner but completely different in plot, of course.
The story begins with Gerald Livingston. Gerald is an astronaut who has been essentially relegated to space debris pick up duty. This is fairly mechanical work, but this time he snags something different–it seems to be of alien origin. We then switch focus between an online (this is a bit in the future, so online with a vengeance) reporter, a rich kid in an orbital race, a pot boiler writer in the employ of an anti-technology sect and an oligarchic cabal. Interspersed between these scenes are definitions of potential species ending problems, possible answers to the Fermi problem and scenes of the day.
As we travel through this journey of a novel, Brin shows us a future that seems quite a possible one into which we might stumble. The future is unevenly distributed. There are poverty striken lows and technological highs, there are plotters and paupers and it felt fairly plausible. As the book progresses, it skips forward in time a couple of times and so we get a view of some of the possible outcomes. A fast paced overview of potential futures. Cool.