(they're tech driven but not in a bottom-up way, there's a core committee that tries to make decisions by consensus but which, if necessary, vote)
Some quotes from postgresql.org:
"A PostgreSQL database developer is someone who is actually working on the project, not someone using it to develop an application or a website."
"Membership on the steering committee is by invitation only, by the other steering committee members, ..."
See who actually controls the direction of the project:
http://www.ca.postgresql.org/devel-contrib.html
