I added a custom search provider to Chrome with an affiliate tag for an organization I like to support, so whenever I want to find something on Amazon I just type "a [query]" and it automatically applies the affiliate tag and takes me to the search results.

Here's the URL for EFF (with "%s" for Chrome search templates):

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dap...

I was thinking about Amazon affiliate referrals for charity just the other days after a friend posted his charity's Amazon Smile referral link. Of course the Smile payout is a fraction of what the affiliate percentage pays. I was thinking about just having a page of with maybe the current top 50 items (five rows of ten) for the week in Amazon's sales rank - as cards with thumbnail and name/price/rating. Then I'd rotate through charities each week based on visitor input, verify the week's haul for them and cut a check to the charity. An alternative to the top 50 items would be to incorporate items related to LifeHacker's "best times to buy" lists. I figured I should just double check the TOS first and haven't had the chance. It's interesting to see others thinking about this.

They closed down all charity and affiliate related projects and replaced them with smile to make it cheaper. aflattr.com + socialvest.com

There are services that will automatically insert a target affiliate tag into every link with an affiliate program, even overriding any existing affiliate tag.

But you need to be careful; Pinterest made news a while back for using a service like this (Skimlinks), without telling people, and it was a bit of a brouhaha.

Hm. I wonder how Amazon/other affiliates see this? I mean, it's obviously different from, but reminds me of, those malware operators/dodgy ISP's injecting their own referral id into links.

Is there any precedent of sites with user submitted content doing it on their own sites?

Yes, lots of it. There are even service (e.g, Viglink - http://viglink.com/) that specialize in replacing/modifying affiliate links automatically.

What the companies running the referral programs think of these services is unknown. I can't imagine they like it...

Amazon actively shutsdown projects, which automaticly replace affiliate links. Most still running projects are just too small to be noticed yet.

This was how pinterest was making money at one point IIRC -- they stopped after people started turning on the idea.