The big problem with the huge social networks like News Corp (NYSE: NWS)'s MySpace and independent Facebook is that there has been no way to target their millions of users. The visitors to these sites cannot be easily grouped by interest or content use the way that users of sites like Yahoo! (NASDAQ: YHOO) can be.

According to Reuters, "MySpace, the world's largest social network, is releasing details of how it is building discrete audiences out of nearly 110 million users worldwide in a format it calls HyperTargeting." MySpace claims it has signed up 50 advertisers to use its system, which collects data from the information pages of its registered users to help marketers reach their targets.

The news service adds that MySpace began by identifying audiences in 10 major categories, such as music, travel and sports, and is now creating 100 sub-categories within those groups.

News Corp has already admitted that it will miss its interactive division target of $750 million in revenue for the year. Part of that is because, despite its size, advertisers have had difficulty tailoring messages for the diverse user base at MySpace. Revenue at the large internet portals runs into the billions of dollars a year, partly because their content is already divided into segments like money, entertainment, sports, and travel.

Privacy advocates are likely to come out of the walls, now that MySpace has launched its new program. They will argue that looking at member pages at the social network and using that information to send them marketing messages undermines their rights.

Too bad. If they don't like it, let them join some other social network. Mr. Murdoch needs to make money.

Douglas A. McIntyre is an editor at 247wallst.com.