From the post:
Welcome to OrientDB – the first Multi-Model Open Source NoSQL DBMS that brings together the power of graphs and the flexibility of documents into one scalable, high-performance operational database. OrientDB is sponsored by Orient Technologies, LTD.
OrientDB has features of both Document and Graph DBMSs. Written in Java and designed to be exceptionally fast: it can store up to 150,000 records per second on common hardware. Not only can it embed documents like any other Document database, but it manages relationships like Graph Databases with direct connections among records. You can traverse parts of or entire trees and graphs of records in a few milliseconds.
OrientDB supports schema-less, schema-full and schema-mixed modes and it has a strong security profiling system based on users and roles. Thanks to the SQL layer, OrientDB query language is straightforward and easy to use, especially for those skilled in the relational DBMS world.
Take a look at some OrientDB Presentations.
A new version of the documentation for OrientDB. I saw this last week but forgot to mention it.