I think RightOn makes the crucial distinction in my mind. I try hard not to blog my personal grievances. I do however sometimes "complain" about ugly design, muddled thinking, the state of the world, etc.
That said, if you consider your blog a more personal and intimate thing, I'm not sure it would be out of place. A personal blogger (dooce, for example) could complain without it feeling even remotely out of place.
» Amazon Associate ... Last Reply: 1 month ago by davidhayes.
I'm an Amazon Associate, but I've not made more than $10 with it.
Advertising--and affiliate programs--are essentially a question of scale. If you have 100 visitors a month, it's probably not worth much effort to "monetize" a site. If you have 100 visitors a minute, even the most incompetent advertising/affiliate strategy is likely to make money.
I'd add, however, that both Amazon's program and Google's AdSense take most of the work out of doing it. So it's not as if you're wasting a great deal of time by signing up and making very little (or no) money.