Recently, on irc, there were couple of cases where someone wanted to use uuid as datatype for their primary key.
I opposed, and tried to explain, but IRC doesn't really allow for longer texts, so figured I'll write a blogpost.
Every now and then there is someone on IRC, mailing lists, or private contact which asks about rules.
My answer virtually always is: don't use rules. If you think that they solve your problem, think again. Why?