I believe Hi5 is a big PostgreSQL user. They gave a talk on how they use it about 7 months ago.

POSTGRES AT HI5, Paul Lindner / Ram Gudavalli, June 12th, 2007

- http://www.inuus.com/talks/hi5_pug_06122007.pdf

We do: http://www.acunote.com (Agile Project Management)

We are.

http://www.massify.com

Justin.tv does.

Disqus does.