How do I buy traffic from webesites using openx? I went to their official websites but have no idea how it works. Seems to be selling a ad management software.
OpenX started off years back primarily as an ad management tool. They opened doors to their market years after that. You need to contact them the get on:
http://openx.com/product/ad-exchange-for-ad-buyers/
Or you can access their inventory through the various DSPs, like Sitescout for example.