OpenX is free. It was completely free until last time I looked but now they have this Enterprise version. Anyway, its used by companies such as Groupon, its much more sophisticated solution than Adslot. OpenX over 150,000 websites signed up. If you're an advertiser, you can sign up for free and put your ad on over 150,000 websites on their network.
MediaMotive is a self serve platform. Why don't they use Adslot but this "mediaMotive" if Adslot was so good?
WFM Price at posting:
7.5¢ Sentiment: Sell Disclosure: Not Held