From PostgreSQL wiki
My name is Richard Stephan. I currently work at the NYISO, and started using PostgreSQL 8.0 in 2005 for my own needs. In January of 2009, I finally convinced management to use PostgreSQL instead of Oracle for one of the applications. It was successful, and others have been created since.
As an advocate for PostgreSQL, I started a local users group in the Capital District of New York State - NYCDPUG.