I was in a discussion with a guy whom I consider to be an above average technologist.  He did a cursory investigation of some of the new databases on the market, among them MongoDB and CouchDB.  I was asking him what he saw as the biggest benefit of these document databases, and part of his answer surprised me:  "Well, and obviously they are very good for storing documents."  What kind of documents, I asked.  "You know, Word docs, Excel spreadsheets, that kind of thing.

Huh?

This served as another reminder to me of why it's important to stay up on these technologies in a way that goes beyond the buzzwords.  For the record, that is not the way documents are defined in today's document databases.  The documents are records of a sort, with fields and values, such as FirstName="Billy", LastName="Bosworth".

One reason (among many others) that they have become popular is because they make life very easy on developers.  They are simple to set up, and very flexible in the way they can be populated.  This means a developer doesn't need to spend time on complex data model changes as the needs of the application change.  They data structures are designed to be completely flexible from "document" to "document" in the database.

We'll talk more about these technologies later, but for now, this encounter served as a good reminder that there are still a lot of folks trying to get their head around these new technologies -- even ones that you may think have it down pat.  Ask lots of questions, then validate them with some basic research of your own.