It's not really a functionality issue. MySQL just works.
The PHP API is incredibly direct and there's little development overhead.
Postgres on the other hand always felt kludgy for small projects. Just getting it up and running and creating databases took longer than with mysql. And phpMyAdmin is a tool most people are familiar with, for which I can't even think of the postgres analogue.
Pardon my butchering of the phrase but postgres is a hammer and mysql is a scalpel, and most projects call for a scalpel.
You forgot to mention, that MySQL has no transactions support.
Seriously, before claiming your beloved choice as "superior solution" would you mind as much as to learn something about competition you dismiss as inferior?
For one I cannot wait PG go become popular—maybe when more people start to use it and start to shoot themselves in the feet will they shut-up about superiority.
Mysql has had quite solid transaction support for many, many years. It hasn't been the play database you think it is for a very long time. This seems like an important topic to you so you should seriously consider looking in to it.
MySQL was great, we all loved it. It allowed many real businesses to make real money without the overhead. Then the oracle thing happened. In the end they are all just tools. Its not really interesting to have a religious debate over tools.
The PHP API is incredibly direct and there's little development overhead.
Postgres on the other hand always felt kludgy for small projects. Just getting it up and running and creating databases took longer than with mysql. And phpMyAdmin is a tool most people are familiar with, for which I can't even think of the postgres analogue.
Pardon my butchering of the phrase but postgres is a hammer and mysql is a scalpel, and most projects call for a scalpel.