Amazon has launched Context Links Beta program. The idea is that you insert a little Amazon script into your pages and when the page is open in a browser the script identifies words and phrases it thinks are relevant and makes them links to whatever Amazon products.
I enabled the script on my blog's frontpage (pinky double underlined links) to see how relevant it is and here are the results:
Well, sure there are lots of opportunities for improving relevance, but still not bad at all for beta
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