The company I work for runs a web site that gets a little over fifty million hits a month. We are looking at replacing our existing custom-written ad server with a prepackaged solution. It fundamentally must be able to scale up to this level of traffic, which eliminates a substantial number of solutions.
Our servers run Linux and so any ad server would obviously need to run in Linux.
Anyone have any software and (less important) hardware recommendations for ad serving that can easily handle 50,000,000 hits per month, and that can scale up modestly into the low nine figure hits/month? Happy to hear about Windows solutions, though we definitely will not be running those.
Does it need to be a standalone solution? If not, I've had great experiences with Google's Ad Technology, which I believe the "premium" solutions allow you to have custom ads, not just AdSense text.
Give OpenX a look at. They have a free hosted solution for upto 100 million impressions a month. Or you can host your own Ad-Server. I used there phpAdNews back in 05 and it was a very powerful and great ad tool. They changed there name at some point...
We were running OpenX for a while, eventually got 0-day'd and ze russians installed a php rootkit. I suppose it can happen to any software, just thought I'd mention that you should plan to run it in isolation.