Lots of efforts and discussion around Document Databases, like CouchDB and MongoDB, in the .NET Developer Community. When you really start to get involved in the technology and become a part of the discussions it really makes you think about why you are using a relational database, like SQL Server, and how you are using it.
I first started hearing about MongoDB from the guys over at TekPub. They use Rails, MongoDB, MongoMapper, and MySQL, all open source technologies, as the technological basis for their wonderful business. In fact, they switched from ASP.NET MVC and SQL Server because not only did the open source technologies provide a better development story but saved them a bundle of money. You can read the InfoQ interview here which is quite fascinating and mentions a lot of technologies.
Just to show you how the Microsoft .NET Developer Community is embracing this technology, you can see a list of .NET Drivers for MongoDB. Note that they have LINQ Support :)
Then Oren came out with Raven DB, which is a document-database focused more from a .NET Perspective.
And then lately the European VAN has been having some interesting meetings on NoSQL. They had a general presentation on NoSQL and you can watch the video here. Recently they had a meeting on CouchDB, which was excellent. You can watch the CouchDB video here. And tomorrow, Monday June 7, the European VAN has a presentation on MongoDB.
Also worth mentioning is a free online book on CouchDB, CouchDB: The Definitive Guide, which has some really interesting thoughts on the technology in general. Read the Introduction Section just to get a feel for the technology.
I am personally starting to question the use of SQL Server, and relational databases, in my projects. In many cases, a relational database does not have to play as important a role in my web applications. A document database, like MongoDB or CouchDB, may better suit my needs and increase the performance and scalability wonderfully. A relational database, and a free one, can take a smaller role for simple tasks where it makes sense.
Lots of wonderful open-source software ( OSS ). I realize more and more how easy and inexpensive it is to start a business and create solutions for clients using OSS.
David Hayden