My two cents, which are rather opinionated. You've been warned.
Mostly the moneymaking is done through affiliate marketing. So, related advertisements on the blog that people are intended to click through. Each click nets a small amount of money to the blog owner.
I hate blog advertising (and most web advertising in general) because the fact is that you only get about 2-3% of your visitors clicking on those ads. So in order to make any foreseeable money you need to advertise EVERYWHERE. All the time. With each new post. The focus usually becomes the money, and therefore these blogs have generic articles (often copy-pasted) that may or may not be valid to the person;. They become very impersonal and are loaded with keywords to make the advertisements more related.
There are a number of members of Chaz who essentially only post when their blog has a new post, in order to get hits and hopefully (for them) clickthroughs. I won't point fingers, but to mew it's pretty obvious. Some of them are stealthy and many Chazzers don't even notice, replying to them as usual.
Most communities get very bored/annoyed with these people fast. Many of my friends have tried making money blogging in hobbies/industries they like, and quickly wound up tarnishing their name in the communities due to how much pushiness had to happen to make the money.
TL;DR: There are better ways to make a buck on the internet.
