What are the canonical NoSQL resources for people who never used this technology?
This is a tough question in the sense that there are several NoSQL databases out there, and they're all slightly (sometimes radically) different from each other.

An important concept to understand for NoSQL technology is that of Brewer's CAP Theorem, so I've provided a link to a good article on it.  For a brief, graphical overview on the CAP Theorem, you should also look at Nathan Hurst's blog, a Visual Guide to NoSQL Systems.

Personally, I have experience with MongoDB (school) and Cassandra (work).  Now that I've used Cassandra for a few years, there are a few good resources that I can recommend:


Cassandra High Availability by Robbie Strickland
Webinar - Getting Started with Apache Cassandra by Rebecca Mills
About Apache Cassandra - DataStax's documentation


As for MongoDB, I have read several books on the subject and here are two (that I think) are really good:


MongoDB In Action by Kyle Banker
MongoDB: The Definitive Guide by Kristina Chadrow