I stumbled on this "tactic" if you can call it that - by accident. I launched a fan site for a kid who was on American Idol (happened to be my BFF's nephew, Alex - not Adam - Lambert) back in January. I posted on it regularly until it got a hefty fan base. They're rabid fans.
Alex got booted off Idol but went on to star in a web reality TV by Simon Fuller (it's a 24/7 web stream called If I Can Dream). So the updates had to be more frequent because viewers wanted to know what he did 24/7 - and they commented all day and night too.
I was handling it good but then had to get some WORK done, so I emailed 2 of the biggest fans - and gave them admin access to the site so they could post content and manage comments.
Those girls have taken over the site! Whenever I *do* have something to post, I log in and it warns me one of them are already in there posting it!
It's great - I know they know their stuff, they do a good job because they're passionate about the subject (Alex), and they live on opposite sides of the world so one handles Alex's late night escapades and the other his daytime happenings.
Now this was a coincidence - and I truly NEEDED their help. And still do. And I want Alex's site to succeed as a real fan, not as a marketer.
BUT...it got me thinking that for other niches, you could do this!
1.) Find a niche topic that has people passionately/emotionally posting about it. A topic where forums grow rapidly and people hunker down to become "veterans" of a site to discuss it.
2.) Get the blog going on your own with frequent content until it's getting good traffic.
3.) Watch for who is the most active and vocal and positive influence on your site and praise them for their contributions.
4.) Award them with admin access to your site where they can post and moderate. Maybe choose a couple/few people.
5.) Ease your way out of it. Work on something else. It runs on autopilot.