Too many negative experiences with overeager matching algorithms. Yes, it's helpful to show me ads for spades if I'm searching on Google for "buy spade", but Am

Too many negative experiences with overeager matching algorithms. Yes, it's helpful to show me ads for spades if I'm searching on Google for "buy spade", but Amazon will not stop suggesting things to me that it thinks I "might" be interested in. They seem surprisingly bad at it too; I looked at a TV costing around £500, and subsequently got an e-mail every few days containing a list of their entire stock of TVs, without any consideration of price. If I'm looking at one worth £500, I'm probably not interested in a TV that costs £150 or one that costs £1500. They do badly on ebooks too, where the recommendations just seem to be "other books by the same authors you've already bought from", which I barely need; what I'd like are suggestions of similar books from other authors that I don't know about yet. I feel like I don't mind seeing ads that I'm interested in, but there is a difference between that and being shown hundreds of ads that I might be interested in. I guess a sufficiently smart recommendation algorithm could theoretically overcome that eventually, but it seems to be a pretty hard problem since it's apparently not been well solved yet.