just wanna to share that Instagram use PostgreSQL. excellent ! this company worth for 1 billion is powered by PostgreSQL
Click link below
http://highscalability.com/blog/2012/4/9/the-instagram-architecture-facebook-bought-for-a-cool-billio.html
http://instagram-engineering.tumblr.com/post/20541814340/keeping-instagram-up-with-over-a-million-new-users-in