My friend and I just built a search engine for used cars. The backend is Django, Solr, Postgres, with RabbitMQ + Celery driving the webcrawler. All running on an Ubuntu Server on EC2

Right now we're indexing ~500GB/day, and hoping to have more listings than Autotrader.com soon =)

Would love feedback, if any of you are into cars: http://carsabi.com