The following is a very interesting post about different database technologies and when to use them.
It is a good way read that helps you to explain to people that you do not have to use some DB tech only because is the new cool boardroom word 🙂
When to use Cassandra, MongoDB, HBase, Accumulo and MySQL
Another relevant post on when to choose SQL and NOSQL Visual Guide to NoSQL Systems
The last post is an overview of database technologies and then a case for Block-chain as a distributed database. Blockchain technology – a very special kind of Distributed Database