A longish piece from Slate on our old friends RFIDs — Radio Frequency Identification Devices — which are feared and admired for their ability to hold all sorts of data about what you’re doing, buying, washing or eating. Earlier this month Hitachi announced the release of a tiny wireless ID chip that can be “easily embedded in bank notes.”Although the story doesn’t focus on it, it makes a good point: Whereas privacy advocates — fearing these things may hold data about our purchases etc well after we left the shop — may be silenced by the idea of a ‘kill switch’ which disables the tag at checkout, presumably the same wouldn’t really be a good idea in currency. So why exactly should we have RFIDs in our currency, and what does it mean for us? More anon.