I’ve temporarily managed to increase the sanity of my Amazon recommendations. Unfortunately, they’re still useless.
Page 1: 8 Destroyer novels, 4 Girls Bravo manga, 3 Grenadier manga.
Page 2: 2 Ai Yori Aoshi Enishi DVDs, 1 Ai Yori Aoshi manga, 2 Destroyer novels, 2 Kaleido Star New Wings DVDs, 2 UFO Ultramaiden Valkyrie DVDs, 2 Nadia DVDs, Castle in the Sky DVD (which I hadn’t marked owned yet), a Hyper Police manga, and disc 1 of Magikano.
Page 3 has another half-dozen Destroyer novels, some more anime DVDs, and some more manga. Ditto page 4. And most of page 5. The first non-anime, non-manga, non-Destroyer item is a Lacie external hard drive at #72. The second is a Logitech universal remote at #79. The list ends at #85, with only three more non-anime, non-manga, non-Destroyer items. Those final three items are the ones I’d be most likely to actually buy, because I’ve already got enough anime, manga, and Destroyer novels to last me for quite a while.
Amazon Japan, on the other hand, has a completely separate database, and I’ve been careful not to over-train it. Its knowledge of my interests and possessions is much narrower, and as a result it offers me hundreds of things that I might want to buy at some point. The first few pages are heavily oriented toward Hello!Project merchandise, but that’s the bulk of what I’ve actually bought from them in the past. The big difference is that there are things I actually want on both page 1 and page 31.
The last few items on page 43 are pretty weak, but page 42 had five DVDs of pretty girls in bikinis, one of which I found rather appealing. Advantage: Amazon Japan.
The net result is that the site I’ve bought more from and rated a wider variety of items on offers me a much narrower selection of items to purchase in the future, and mixes them up poorly, so that most of its recommendations are for the items it has the most of, which are the items I’m least likely to buy that many more of. There are over 120 Destroyer novels, and the only way to keep them from dominating my list is to claim I’m not interested in any of them. Which isn’t true, in the long run, and negatively impacts future recommendations if I do it.
And, sadly, I can’t clean up my “not interested” list, because Amazon’s tools weren’t written to handle 6,000-item lists. Their official recommendation is to create a new account, which just isn’t worth it.