This is a difficult book to review. On the one hand, it's a good near-future conspiracy thriller. On the other, it's a wonderful exploration of a possible evolution of ubiquitous computing and networking and their effect on society.
Some of the ideas that Vinge presents seem so useful and cool that it's hard to imagine that they won't come true. On top of this, the technology is not too far off what we have now (and certainly a lot of things are currently moving towards what he describes).
In addition to the neat gadgets, there's some really funny stuff about the way that subcultures have developed with the almost total internet penetration of life. My favorite is probably the (mostly play) battle for supremacy between two "belief circles" - these seem part fan club, part cosplay group and part online game. There's also some ideas about schooling and work that are a lot more serious. Both the comic and workaday descriptions of the society are thought-provoking.
Overall, very good. I'm certainly going to read it again, just to really explore the details of social change that Vinge presents here.
In tangentially related news, I recently bought myself a PDA for the first time. It's been quite useful in the ways I expected it would, but Vinge's novel makes me feel like I'm now on the leading edge of a social revolution. A little bit, anyhow.
Rainbows End (Amazon)