Postgres was just not popular enough, I think; it's still considerably less popular than MySQL, and familiarity and operations counts for a lot. So I think the

Postgres was just not popular enough, I think; it's still considerably less popular than MySQL, and familiarity and operations counts for a lot. So I think the number of "marquee" names falls about in line with what one would expect. Facebook is very nearly out of the running because of its PHP lineage, Amazon has very close ties to Oracle, but Google could probably have easily gone either way, but MySQL is popular, so it probably got there first.