Stefan Edlich adds another object oriented database to the long collection of non-relational databases:
The HSS Database is an object oriented database management system (OODB or ODBMS) for Microsoft .NET, Silverlight and Windows Phone 7. HSS Database gives developers the ability to store and retrieve objects from their applications with extremely high speeds compared to other solutions, and with a small footprint (~100KB).
With so many non-relational databases and quite a few well established object oriented database management systems out there, I doubt a new and commercial offer will see any significant adoption.
Original title and link: NoSQL Databases: HSS Database for .NET, Silverlight, and WP7 ( ©myNoSQL)