Since social networking hit its tipping point, mainstream websites are cannibalizing eachother and fighting for members. The future leaders of the pack have gotten smart and developed niche sites that slice the pie into tiny, yet dedicated, slivers. What follows -- in alphabetical order -- are some of the most promising examples of, dare we say, social networking 2.0, as selected by the marketers at Renegade.
These rankings were principally subjective, based on our intuitive understanding of the social networking universe coupled with extensive industry research. Our information sources include syndicated research data and extensive conversations with media reps and several trade publications.

We've included Nielsen//NetRatings unique visitor estimates when available.

Now let's take a look.

aSmallWorld
Membership with the most exclusive social networking site on the web has its privileges. aSmallWorld is an invite-only space for wealthy jet setters and bold-faced names. You'll need to know someone on the inside -- like for instance Tiger Woods, Ivanka Trump, Paul Allen or Naomi Campbell -- in order to cadge an invite. The philosophy is that most people in the world are separated by no more than six degrees, but to get into aSmallWorld, you need to be within three degrees of the elite. Once on the inside, members gain access to private villa parties in Capri, masked balls in Hamburg and polo matches in Buenos Aries.

The founder, a Swedish count, wanted to aggregate the world's most interesting people sharing the world's most interesting information. He figured that in a safe, exclusive environment, the hoi poloi will be more willing to open up and share info with each other, like where to find the best sushi in Tokyo, the best nannies in Manhattan or an Aston Martin for sale. Unlike most social networking sites, membership skews older; 90 percent of users are older than 24.

For marketers, aSmallWorld is like shooting goldfish in a barrel. High-end, luxury brands like Diane von Furstenberg and Moet & Chandon can speak directly to the elite by buying ad space on the site. The psychological drive for exclusivity and status that fuels the popularity of the site also fuels demand for the luxury goods that advertise there.

Author notes: Drew Neisser is president and CEO of Renegade Marketing Group. Read full bio. A special thanks to Renegade's account planning director Shana Lory and online trendspotters Emily Vernon and Ivy Buckly for their hard work on this piece.