What I'm taking away from the article is the ol' KISS prinicple. I don't see why building on an RDBMS necessitates added cost, though. I can think of at least

What I'm taking away from the article is the ol' KISS prinicple. I don't see why building on an RDBMS necessitates added cost, though. I can think of at least two production-quality products that are free, and depending on the application, using the structure provided by database tables and SQL queries can actually be simpler than using a mishmash of hashtables and XML files.