They Know Me So Well

'We know you better than you know yourself' declared Amazon in their latest email to me. Well, that's a bold claim, even for Amazon, so I thought I'd open this one and have a look...
  It seems the 'me' they know so well is some kind of alter ego of mine, with a lively interest in 'joggers' (they appear to be some kind of misshapen trousers) and 'combat work pants' (ditto), a chap who might well be tempted by the prospect of owning 140 jam/pickle jars, fancies owning a Hornby OO train set, and is keen to buy, er, women's dresses. Sometimes I wonder if these algorithm things are quite all they're cracked up to be.