[jordz]

Cassandra is mentioned, I agree it's great for storing metadata and can be used to build efficient graph implementations but it's cited for Graphs and Relationships? I think that can be misleading as Cassandra is a a distributed column based key-value store.

[wenc]

I noticed that too. I don't want to gainsay the author's experiences, but it sounds like the author is describing the job of a data analyst who happens to dabble with various software. I don't get the sense the author has in-depth knowledge about the tools he lists.

Also, I don't know about putting Mongo and Cassandra under "Tools for working with unusual datasets".