It's entirely possible, given my propensity to swear and rant and declare things to be Web Scale, that folks might get the idea that I do not like our newer NoSQL bretheren. Quite the contrary - I think almost all of them are exciting and well suited to various tasks. My biggest beef is in thinking that a single technology should be square-pegged into every round-hole anyone can find. This holds true for Drizzle and MySQL as well, by the way. Just because I work on Drizzle does not mean I think Drizzle should be the method of data storage for every blessed thing on the face of the planet - that would be silly!
I bring this up because I had my first instance of thinking that Cassandra might be a good choice for a project someone was showing me yesterday. In this case, the project was collecting data about events, but it as the data was events about real-world interactions, the particular information stored about each collected event had the potential to be wildly different. It could have been modeled (eventually) in SQL, but it seemed much more likely that a column-store like Cassandra would be entirely more suitable.
I was also considering CouchDB the other day as a choice for cue storage backing a show-control system I'm working on, because of the document storage model. In this case, I believe I will use Drizzle because integrating with the pluggable protocol system will allow me to just speak the Open Sound Control protocol directly to Drizzle, and that's actually more important in this case.
Point being - when I rant about the suitability of NoSQL solutions, I'm mainly complaining that in many cases it seems to me that they're using them because they're popular or trendy and not because they are or are not actually suited to the task at hand. If they are suited to the task at hand, then by all means - use them. Heck- I've been convincing people to use NDB for years when it's the right fit.
We don't need a winner in the data storage world - we need a vibrant culture out of which tools suitable for tasks can be selected.