I'd be more impressed by posts like these about "building an online community" if the advice didn't always come down to three basic rules:
1) Group blog (translation: either have a blog big enough to support other writers, or write for some other guy in the hope of exposure, and if you're the newbie that ain't a "Name" guess which side you're on.)
2) Cater to a niche, the smaller the better, because Kos et al have the whole "general political analysis" field sewn up for some reason;
3) For God's sake, don't write anything longer than a few paragraphs, that's not what this medium is for.
(Unless you're digby. Or Glenn Greenwald.)
Meh. This reminds me of the advice of neoliberal economists, who ignore actual economic history in favor of pointless theory. Honestly, if you look at how most blogs actually got popular, the lessons would be:
1) Exploit network effects;
2) Get other writers to make your content by hosting diaries instead of linking to smaller bloggers;
3) follow Andrew Sullivan's dictum of media success: ignore those who are smaller than you, while trying to provoke those larger than you into responding angrily to your criticism.
Me, I'm just gonna keep prattling about the Overton window every few days.