There's already lots of different types of "database systems" floating around. Map/Reduce approaches to large-scale data processing has been getting most of the hype in the F/OSS space and columnar approaches in the enterprise spaces.

An area that is finally starting to get some love are approaches like Mark Logic's "XML contentbase" approach -- native XML data store that's wicked fast. Of course, I'm biased but I think MarkMail (http://markmail.org/) is a pretty slick, public example of it in action.

This would be easier to understand if Aster Data's website (http://www.asterdata.com/) didn't seem like a bunch of marketing jargon.

I disagree. A company's website should be a marketing vehicle, and Aster Data's site is actually far more readable than most enterprise software vendors' sites. They do a good job of breaking down the specific reasons one needs such a scalable database, identifying failures of traditional databases in specific industry. I'm quite impressed with how understandably they present themselves, given the material and their target audience.

I already know why I need a scalable database, it would just be more interesting if I knew something about the tech underneath.

I was told that what the world needs now was love sweet love. Clearly, I was misinformed.