No matter how well designed or "active" websites may appear, if its only function is to send you to some affiliate offer - it's spam. The best of them are very good at faking legit websites (even having an active "community" engaged in "discussion"). They are extremely good at faking normal human activity and I don't see the end to it. There's virtually nothing you can do that a script can't do also.
I don't think this definition is quite right.
A site can be good and still have as its raison d'etre referring you to a product manufacturer. After all any sales website is doing the same thing, there's just a certain distance between affiliate sites and the manufacturer.
Don't get me wrong, a lot of affiliate sites are bogus, unhelpful and given unwarranted prevalence in SERPs; but that doesn't make them all bad. For example in the UK there are sites that offer money back on all purchases - they're affiliate sites that share the affiliate fee with the purchaser.
Google believes that pure affiliate websites do not provide additional value for web users, especially if they are part of a program that distributes its content to several hundred affiliates. Because a search result could return multiple sites, all with the same content, they create a frustrating user experience.
And here's the rest of it: http://bit.ly/KWS1cz
>For example in the UK there are sites that offer money back on all purchases
I don't see the relevance.
The only purpose of those sites is to get you to follow affiliate links.
Were you trying to refer to some sort of passthrough short-linking system or something?