NoSQL
NoSQL (Wikipedia)
MongoDB
MongoDB Tutorial (with a live MongoDB shell prompt)
mongodb.org
mongly.com: lots of MongoDB documentation
MongoDB.pm (CPAN)
MongoDB.pm (github)
10gen
BSON
BSON specification (bsonspec.org)
JSON specification (IETF)
JSON (Wikipedia)
Miscellany
This presentation
CAP Theorem (a.k.a. Brewer's Theorem)
BigTable