Open Source Advertising

Have a need to host your own ad server? Don’t want to pay a lot? OpenX Ad Server makes this possible.

“OpenX Ad Server is a powerful open source platform that manages advertising for more than 150,000 websites in over 100 countries. More than 300 billion ads run through OpenX Ad Servers each month. And since it’s available as a software download or as a hosted service, you can decide to run it yourself or let us take care of managing the infrastructure for you.” from

OpenX Ad Server is fully supported on Apache web server in a Linux environment and is very flexible in terms of implementation. System requirements are fairly common, the main requirement being PHP support. MySQL and PostgreSQL are supported for database connectivity.
There is also full community support for this product with the usual forums and blogs. Version 2.8 has just been released.
For IT shops not wanting to host this, there is of course and hosted version available which includes up to 100 million ad impressions per month for free.

Just released yesterday, OpenX Market is a new platform to maximize your ad content and ad space. The idea is to bring advertisers and publishers together in an ad exchange. While this is not a new idea, it is becoming more relevant as advertisers move more from offline to online.
OpenX News Article