Over the last decade and a bit, I’ve bought quite a lot of stuff from amazon.co.uk. And as I’ve bought and rated lots of stuff, they’re able to make some often quite useful recommendations – these are far from perfect, but they’re often the way I first realise that something I want is available, so I do take a look through them from time to time, and click the relevant thingies to tell them which items I already have, and which I have no interest in.
It all seems to work on the basis of “people who bought item A also bought item B, you’ve bought item A, so you might like item B”. And this actually works a lot of the time – though it occasionally pops up some delightful oddness. For instance, because I gave a high rating to Necrophenia by Robert Rankin, apparently I should be really keen on this:
One of the finest examples of Artificial Stupidity I’ve seen lately.
 I’m not quite sure how long this has been going on, but it’s certainly over ten years
 Major understatement time
 Books, CDs, DVDs, a TV, my MacBook, bin liners, cables, lenses, my lovely lovely Kindle and probably some other stuff I can’t recall right now
 Technically, those might have been from a seller on Amazon Marketplace
 Rather like Artificial Intelligence, only much more common