Vernor Vinge creates in interesting universe, where the level of intelligence possible is determined by physical laws that change as you move away from the center of the galaxy.

In this universe the Singularity is only possible in a certain zone of the galaxy known as the high beyond, as opposed to places like the slowness that are limited to things like the speed of light.

While this goes into some pretty dubious physics, and is actually not explained at all.
It makes for a better introduction to the concept of the Singularity and it's coexistence with less sophisticated intelligences than what Charles Stross does in Singularity Sky.

Vinge plays with different types of sentience in this book and I especially enjoyed the networked pack intelligence of the Tines race. Where it takes at least 4 members in a pack to reach sentience and it is possible to swap new members to replace dead members, creating a new personality while preserving memories from the lost members. It is interesting to see the different approaches Tines take to crating and maintaining their packs/individuals.

This was my first Vernor Vinge book, I really enjoyed it and am looking forward to reading more of his work.