[nkallen]

I think you've given a good suggestion for upcoming blog posts.

Gizzard is used by two systems at Twitter. One of them is called FlockDB and we are working on open-sourcing it (indeed, FlockDB is why we open-sourced Gizzard). FlockDB stores Twitter's social graphs. I cannot tell you (yet) how many QPS we do do or how many edges there are in the various graphs, but suffice to say its a lot and we run lots of complicated queries like "who follows both @aplusk and @oprah but does not want any of @aplusk's retweets," etc.

Gizzard is NOT perfect. But we think you'll find it is resilient to a large class of failure scenarios (that have, in fact, occurred over the last year, so this is not just the theoretical fault tolerance of a project that's been deployed on a small web site with simple requirements). With your help, it could be even better.