MTV Networks is rolling out real-time ad targeting in online videos served through its network of sites, reports Mediaweek.  The company has enlisted online ad measurement firm Quantcast to enable advertisers to target audiences accessing its online video content based on specific demographics and lifestyle, and do so in real-time.  Quantcast says its technology can pinpoint the audience for a given piece of content at a given moment by combining data from a variety of sources such as panels and ISPs.  It describes the system as a mass scale inference model.   MTV ad sales executive VP Kevin Arrix said the tech allows us to mine our audience across the entire portfolio.   Mediaweek says MTV is rolling out the tech across its online network including web sites for VH1, Spike, and MTV s Tribes ad network.  Read more at Mediaweek.