I don't do anything for money on my family blog. I would just feel really, really weird having pictures of my kids on a blog that earned money. I know it's not "stage mom" behavior, but it sort of feels like the beginning of a slippery slope...
But, on my "fun" blog, I do have ads turned on and an Amazon Associates account. I don't do it for the money, I absolutely LOVE what I write about, but if I get some kick back from Amazon for doing what I would do anyway, what's wrong with that?
I think if you change your content or your POV just so that you can get the ads and such, then you have a problem. As long as you are being you, why not get paid for it? Isn't that capitalism?