I found a very interesting article entitled "NoSQL Ecosystem" from The Rackspace Could. It dove into the fact that we need an alternative for relational databases to handle the high volume of data these days. Some examples the article gave:
The fundamental problem is that relational databases cannot handle many modern workloads. There are three specific problem areas: scaling out to data sets like Digg’s (3 TB for green badges) or Facebook’s (50 TB for inbox search) or eBay’s (2 PB overall), per-server performance, and rigid schema design.
It's a good read, I would like to hear your thoughts around this NoSQL Movement idea.