Blogging as a Full Time Career?

My wife and I make a good living blogging -- we have, and are always developing, niche sites that take about a month to build into something substantial, so roughly each month there is a new property which we can track for hits and revenue. What works we do more of, what doesn't hit we either revisit strategically (for example acquiring a competitor's site for their google rank), or we just let languish in favor of the more valuable properties.

As far as blogging? I know a guy making a few grand per month, but he's got 30-some sites going at any given time, and can spend as much as 15 hours per day, 6-7 days per week developing, ferreting out and posting content. Like pmichaud, they seem to be niche sites, and if things aren't panning out with some topic, it gets abandoned.

While it's difficult to put a metric on thought work, I think, at least for myself, it's easier to put in my 40-something per week, do a little bit of weekend work in maintenance windows and on-call. And I still make more than he does, plus have insurance for my family. But he's his own boss and loves it. It works for him and his family.

There's probably this extremely minuscule core of people who either through luck or years of brute force, can make a fabulous, lavish living on a handful of blogs, but the big names you already know are basically on the clock every waking hour. Kudos to them. They're definitely the exception, not the rule.