I went to a presentation about CouchDB recently, and afterward asked a couple questions about distribution, how views work, transactions, comparing its design and performance to RDBMSs, etc. It was immediately clear that the speaker didn't really understand the relational model at all (and he kept calling SQL "MySQL"). He couldn't answer several of my questions, but pointed out several times that the technology behind CouchDB is "way sexy". Now, I really like Postgres and SQLite, but I'm curious about the other systems because I'm a bit of a database nerd, and I was hoping he could explain what problems they solve, beyond some handwavey assertions about scaling and reassuring people with an aversion to SQL.
I'm not saying he's representative, but he comes to mind when I hear about a noSQL movement. People whose sole understanding of RDBMSs seems to have come from e.g. _PHP & MySQL For Dummies_, but keep hearing that SQL doesn't scale and noSQL databases are "the new hotness". Talk about the advantages of those systems compared to RDBMSs! And if you can't talk about any collective advantages they have, because they don't have much common ground (which is quite possible), then trying to present them collectively is just going to be confusing.
That may be a pretty big part of the explanation. Most of the apps build on knowlegde rathered in that book, would probably benefit from being released from the constraints of SQL (and on the level of a blog or forum app SQL is more of a constraint than a benefit).
So maybe NoSQL people need a movement after all. The relational people are at _least_ on their third manifesto. Lot of catching up to do!
The various NoSQL-solutions are quite different in nature, the only thing that really brings them together is that they're not SQL, and instead of each of them doing their own awareness raising campaigns, they probably do well to gang up. I don't even think they should change the name, it's not until now when they've created the NoSQL-umbrella that they're really getting some well-deserved attention.
There are plenty of solutions out there, pick the best one, or whichever one you just plain like more. And that might very well be SQL. Just don't pick SQL simply because that's the only solution you even know about. I think that's a message worth spreading.
I would love to read a detailed, informed comparison of CouchDB, MongoDB, Tokyo Tyrant, Redis, etc. by somebody who knows enough about RDBMSs to realize they don't all suffer from MySQL's limitations. I'm curious what use cases they fit the best, etc., but most things I've read have only been familiar with one or two of them (understandable), or has been very heavily biased towards somebody's pet project or new favorite.
Most advocates of technologies like Tokyo Cabinet/Tyrant, Mongo, CouchDB, etc - don't seem to argue this, instead taking a much more responsible approach of suggesting organizations whose needs are best suited by non-RDBMSs check them out, rather than porting everything over whole-hog.
I suppose what I'm suggesting is that the "movement" frame doesn't match the mindset of most proponents of the paradigm. There's nothing political about it - it's just another (very awesome) technology to consider for certain cases.