CAMBRIDGE, Mass. — Social networking sites (SNSes) like MySpace and its more than 50 million visitors a month include many young and youngish consumers interested in interacting with providers of goods and services, according to a new report from Forrester Research. Author Charlene Li writes: "Marketers who see lots of users congregated in one place want to pursue that place as an advertising channel. But many of the marketers that we spoke with admitted that their initial advertising forays into SNSes–typically run-of-site display ads measured on click-through rates–were abject failures. And marketers who posted profiles on SNSes weren't necessarily winners either, as it was unclear what the real value of a brand having thousands of friends was. Instead, the true marketing value in networks is created not by reach and frequency of a message but by engaging users in co-creation and by encouraging pass-on of brand elements." That could include downloadable elements users can put in their own spaces, for instance.