Google, NuoDB, and the rest
I concur with the fundamental thesis of this article that it will be hard for anyone to replace SQL for most database use cases / applications. NoSQL reminds me of the object-oriented database days, when the claim was made that it will replace relational database technology.
What is true is that relational database technology must evolve to support scale-out datacenter architectures. The likes of Google and NuoDB are well on their way to deliver on that promise. For NoSQL to grow beyond a 100M dollar business, it will have to embrace SQL in some form or the other.