How FriendFeed uses MySQL to store schema-less data →
https://marco.org/2009/02/27/how-friendfeed-uses-mysql-to-store-schema-less-data
Very clever.
I completely agree with their underlying principle: MySQL with InnoDB is a mature, fast, manageable, high-integrity transactional storage engine. You don’t need to toss that out and start over with a young, untested product just because you want a different data structure. You can build a lot on top of it that isn’t necessarily the “normal” way to use it.