What exactly is NoSQL?

Question

What exactly is NoSQL? Is it database systems that only work with {key:value} pairs?

As far as I know MemCache is one of such database systems, am I rig

Answer 1

MongoDB looks interesting, SourceForge is now using it.

I listened to a podcast with a team member. The idea with NoSQL isn't so much to replace SQL as it is to provide a solution for problems that aren't solved well with traditional RDBMS. As mentioned elsewhere, they are faster and scale better at the cost of reliability and atomicity (different solutions to different degrees). You wouldn't want to use one for a financial system, but a document based system would work great.