The stats are staggering. MySpace, the social networking giant, has rocketed from 20 million people in 2005 to over 225 million today, with an annual average growth rate of 513 percent. Social networking rival, Facebook, posts similar numbers, only with a slightly better growth rate of 550 percent. LinkedIn, the business professionls' networking site grew at an average of 182 percent during the same period. A cash laiden dream? Not quite.

One would think that the revenue numbers would be equally impressive. However, Lookery, an ad network specializing on social media offer ads on MySpace, Facebook and Bebo for only 13 cents per thousand times that an ad is 'served,' or CPM. Yahoo's average CPM is estimated at $13. Video ads on Myspace manage to only coin $25 per thousand showings while CBS charges $50 and NBC charges as much as $75 for the same number of views.

Even search behemoth Google, which charges a reduced socializing rate, thinks it may be paying too much to place ads on MySpace. Even Founder Sergey Brin admitted in January to analysts that Google "Hadn't found the best way to monetize the social networks."

The smaller niché networks, it seems, are more successful at turning audience clicks into cash. LinkedIn for example, has a CPM rate of $75. What's the difference? LinkedIn caters to a professional business audience and so the advertisers have a narrower business audience, in addition to clicks they are also charging for premium features and job listings.

Social Vibe encourages members to select brands to endorse their pages. Other services share ads across related sites. Working out how to turn the eyeballs of friends socializing into hard cash remains elusive, even for the big networking boys, but one thing is for certain when they come up with the ultimate model, they'll all want to be your best friend.