Been noticing a daunting dropoff in the number of referrals (clicks) reported for my amazon associates account. I've compared it to my analytics data, conversion rates, and everything else—and something didn't add up. I was seeing a -35% drop of referrals across the board. Turns out Amazon just changed the conventions of their url parameters for such things like searching, and category links. What happens is as follows: old url -> 301 -> new url Any old links from your site still work, but during the redirect referral tags get stripped out. I went through each one of my hand-made referral links (often I link to search results with filters applied) and my numbers are back on par. Below is a screen shot of the problem, and the fix: You can see where the blue line is drawn that there was a significant drop off. I thought I was just having some really shitty days for a minute, but the last two days show that fixing the url parameters in old links seems to have solved the problem. Amazon seems to be on a warpath against affiliates this year. This 'oversight' by them, as well as recent rate changes had my site taking a ~65% hit on overall income. I can't predict the future, but it looks like all signs are pointing to Amazon regarding affiliates more as a burden than as a benefit. I'm not quite sure about the exact changes to the parameter conventions, but it seems like they used to use naked spaces to the more common URL Percent encodings like %20 and etc.