But the problem with them, I find, is proliferation. It wouldn't be a problem if I had one anime wish list on one website and a book one on a different website. The problem is that I'm now up to four online wish lists for books only, and three of those wish lists are with Amazon. The problem is, you see, I can order books in Canada, the US, and the UK, and at different times it's convenient to do one or the other.
Some books are only available in one of those countries and not the others. That's where the beginnings of proliferation began. To begin with, I just used Indigo, the major Canadian bookstore chain, to keep track of my bookish desires, but then I started finding books to track which weren't available in Canada. Then, having established lists in multiple countries, I began to add with impunity, ignoring what country might be the most convenient to order a given book in, and just adding whereever I happened to already be. Indigo still has the bulk of my list, but the others aren't far behind.
You don't need to move around a lot for this to be a problem. Within any one of these countries are several competing online book dealers, most of which probably have this function these days. The result is the same, a fractured group of lists.
In many ways, this proliferation defeats the purpose of having a unified wish list, one place to go from which all books can be retrieved. But it wouldn't be that simple, even if so many books weren't available only in one country, because there are so many obscure and deeply out-of-print books that I also covet. I'm just glad that it's a pain to order books to Italy right now, or I might have a fifth list.