New York based RightMedia has launched a beta version of a new advertising system that lets website publishers participate in multiple ad networks and automatically display ads from whichever network will pay the highest price per impression for their ad space in real time bidding. The service, called RMX Direct, also has a filtering system to prevent malware distribution through ads and enforces publisher criteria. RMX Direct will officially launch in September but is opening up beta accounts now. RightMedia has offered a more complicated enterprise version of the system since April 2005. While the enterprise system has more than 50 participating ad networks to chose from, RMX Direct is starting out with only 8 but will increase in time. Read more at TechCrunch