Adbard
Adbard is a free software advertising network "designed specifically for reaching the developers, architects, users and influencers in the free software community, allowing advertisers to directly communicate with the key customers in this exciting new area."
"The Free Software Community now has an ethical alternative to ad networks that promote proprietary software" said Peter Brown, Executive Director of the Free Software Foundation. "This is a huge win for many of the sites that serve our community. And we wish AdBard and the websites that display AdBard adverts every success. We also hope this will inspire other ad networks to adopt similar policies."