"Most of the other things I have read on this topic have taken a position of "Relational good, Key-value bad" or the opposite." This is part of a rift between

"Most of the other things I have read on this topic have taken a position of "Relational good, Key-value bad" or the opposite." This is part of a rift between the people writing the posts and the people spending their time building Facebooks, Googles, etc. Almost everyone I've talked to who operates (not just plans to) at HUGE scale relies on a combination of key-value stores (commonly known as memcached) and relational databases. That way you get all the speed benefits of something like BDB, without having to re-invent alternatives to SQL queries in [your language of choice] wrapping BDB.