Are affiliate links dirty?

I'll preface this with saying I have respect for Tim Ferris, and dig most of what the guy does. I've enjoyed some stuff out of 4 hour work week, his blog, and am looking forward to reading his next book.

But I observed something I'm not sure how to feel about the other day.

I was reading his blog and saw this review of 37signals latest book Rework. But whenever you click on one of the links to Rework it takes you to Amazon with his affiliate link (tag=offsitoftimfe). So he gets a little bit of money any time someone buys that book from his link.

I'm not trying to flame Tim Ferris here, and please don't think I expect insulting comments about Tim here either as those will be deleted.

What I am trying to do is figure out what I should be doing with this gray area of education + marketing + capitalism here on this blog.

I review excerpts and link to Amazon all the time. I read an insane amount of books. Here's a post from the other day about a book about Game design where I link to Amazon.

Sometimes those posts generate a ton of traffic for our blog, and a fair number go check out Amazon. But I've never used an Amazon affiliate link. It's dawned on me to try, but if I do, doesn't that taint the review a little? Does't the review look a little forced and biased in your eyes then?

There's a similar area of grayness that happens when people buy things like eBooks. A ton of the eBooks out there (maybe not the Kindle versions of non-eBook books), are loaded with affiliate links to other people's products.

So you get this feeling that you bought someone's book to be educated about a certain subject, but that education is soured, because the whole time this person is trying to make some more money from you peddling someone else's stuff. You get left thinking, would these people even be recommending these tools, services, or strategies, if they weren't getting this extra cash on the back end?

If I wanted to see a ton of ads and read something, I'd buy a magazine. But even a magazine has sections that when it looks "educational" but is actually sponsored they have to say "Special Advertising Section". And even tweets now can be bought but those tweets are required to say "sponsored tweet" inside them.

So if that's the right spirit of things (and sometimes the law), when you tweet or mention a book you should check out, shouldn't that mention say something like "affiliate link" or "sponsored link" or something?

I hate more rules though myself, so maybe this is nice that one doesn't have to do this.

What do you guys do or like to see done? I'm a capitalist, and want to increase the money Inkling makes as well. So should I get over my weirdness of adding affiliate links to posts here, or am I onto something and you guys get weirded out too by someone trying to make money on the exact product they are recommending or reviewing?