[jat850]

Sure, a couple I can think of:

- when JSON is the native language of your application, certain NoSQL implementations are beneficial. The value/need for this is changing with more RDBMS introductions of JSON datatypes.

- speed/ease of development/familiarity - sqlite is easy to set up and maintain for small installations/projects, so is mongo or couch or redis - fairly straightforward tradeoff

- leveraging other platforms. Quick example might be wanting to take advantage of Amazon Dynamo or SimpleDB. Sure, RDS is right there too and scales in a similar elastic fashion, but Dynamo especially feels much, MUCH more hands off in terms of redundancy and application design. We use Dynamo since day 1 of its release (we transitioned from mongoDB to Dynamo with 1 day of work) and have not looked back. In our particular project I cannot conceive of how or why we would want to use an RDBMS, it does not fit the task.

I'm not advocating for NoSQL over RDBMS in any given, or especially all, situations. But there are plenty of reasons to select nosql-based implementations.

[intoit]

Dynamo looks very interesting. Thanks for pointing it out.