A recent Guardian Elevator Pitch features my colleague Ben, and his social networking site for cyclists: meandmybicycle.com. But this post isn't just to push his site, it's also to pick up on one of his comments in the article:
"I do believe that social networks are the next big thing when it comes to specific interests. They are just so dynamic and take traditional outlets like magazines - often the glue for interest groups - onto the next level. The wisdom of the crowds thing really means that niche social nets have tremendous value. "
It's a view I'd agree with as well. Now that sites like Facebook and MySpace have peaked, some areas of the media talk about them being in decline. They're not, they've just plateaued as you'd expect with any kind of similar service.
But as users find the limitations of the big one-size-catches-all social networks, so they'll turn elsewhere to networking with people with similar interests. While Facebook is great for keeping up with friends, organising parties, events and other suchlikes, one area it falls down on is the groups for like-minded users to share interests.
The groups that work well are the petition or long-standing fan groups, or the small groups either set up for, say, charity sponsorship (I'm running the marathon, please donate - that kind of thing). The rest tend to muddle around, starting off strongly before petering out, which normally works ok for petitions, but very few of them build a proper community . The rest tend to be inactive personal statements.
Take my own profile: I'm a member of two Exeter City fan groups (and, until I did a mini group cull, a further three) both of which have a similar crossover in terms of membership. In addition, I'm also a 'fan' of Exeter City as well as Exeweb, the independent fans forum, which has a healthy social side to it. Unsurprisingly, the same faces pop up in these areas as well. I'm also on the City fans mailing list, Gnet, and subscribed to the official site. 
So, now I've got over half a dozen different Exeter City fan groups/forums on and off Facebook all of which are slightly different to the others; that is simply too many to realistically keep track off. Exeweb and Gnet are both useful outside of Facebook but they don't allow me to post videos, blogs, or build a supporter profile, or even create a micro-group (post-match Old Timers drinkers, Birmingham Exiles, that sort of thing).
And that's where Ben's site, built using a simple Ning platform, comes in. Ben's site provides all the social networking sites a niche site needs. You can just stick to the forums, or you can get really involved and video bog from Seesmic, post videos, photos, comment on blogs, or create your own group to complain about the signage in Camden, all while building up your own profile, which isn't available on a forum, but may not be specific enough on Facebook or Myspace.
If Facebook could sort of their groups, they'd have another powerful tool in their social media behemoth. As it is, if you're a cyclist or an Exeter City fan, you have to trawl through several groups of low to medium activity that vary in quality and don't quite give that social media feel you were looking for. Niche networks, while unlikely to be as phenomenally successful as Facebook et al and certainly won't overtake them, nonetheless fill a gap in the market and some even have the potential to make a bit of money. Why place a biking equipment advert on Facebook when you can target the social network that solely consist of the exact people you're looking to target?
 That isn't to say the groups can't be a good PR tool, but you're still reliant on getting the numbers in.
 Interestingly, the two Facebook groups I've joined that have a lively and active community are A Cup of Tea Solves Everything and I'm Sorry I Haven't a Clue Appreciation Society. They're an excellent example of how a group can work well.