For some time, I've shown Ad Bard ads on various sites related to free software I run (this blog, Wammu website or phpMyAdmin demo server. I saw it as not that intrusive way for paying fees for hosting of the server which runs this all. Also I found it good idea to promote free software friendly business, but was always a bit skeptical to it's success.
Today the service is supposed to be shut down, though the web site still does not mention anything like that so far. But it was announced month ago to the publishers and I expect it to be true. The reported reason is lack of time
to focus on improving the network and selling advertisements.
I've removed the ads from all my servers and I currently do not plan to replace it with anything else for now. So you can enjoy them ad-free even without AdBlock :-).