ACID Cloud databases to keep an eye on
So far, "database in the cloud" options have been pretty limited. You have Amazon's SimpleDB, which is slow, eventually consistent, and not really a database except in the loosest sense of the word; there's Amazon RDS, which is a managed MySQL instance and scales up, but not out; and of course you can run database server yourself on any of the cloud servers out there (Amazon EC2, Rackspace, GoGrid, Linode, Slicehost, etc etc). But none of these offer one-click scale out ability, which is really the hardest part of database scaling. However, there are a few options cropping up, most of which are in beta.
How we got here: Web App Stores
The recent sudden popularity in web "app stores" is taking off with a rate normally associated with fads, but in some respects is actually to be expected. Still, it bears an interesting similarity with one of the oldest types of websites that the average consumer has seen: directories.
HTML5 Web SQL Database – Intro to Versioning and Migrations
I've been dabbling a bit with Chrome extensions, which have at their disposal HTML5 localStorage and Web SQL Database. And...the web sql database especially is pretty cool. But one thing was bothering me -- if I have a database on the client, how do I maintain the schema? The (simplest) answer is in changeVersion.