tiny tiny tiny tiny RFID tags: http://www.3pointd.com/20070216/rfid-powder-developed-by-hitachi/
Tim O'R on identity: "A lot of people think that there's a single big identity play out there, and focus on technology solutions, but it seems to me that in true bottom-up internet style, we may eventually build our online identities out of a mashup of all the tracks we already leave in cyberspace. (Seth Goldstein has been exploring this idea with Attention Trust.)" http://radar.oreilly.com/archives/2007/02/worldcat_identi.html
Why does the net evolve so fast? Because every time a company gains a competitive edge that they can charge for, technology enables others to rapidly make the same thing available for free. The lifespan of the paid-for facility is short, so companies need to constantly advance to a significantly improved offering that they can still charge for, or find a revenue stream for (which still involves attracting people to use it). As has been pointed out e.g. by Lorcan Dempsey, some companies can feed their revenue stream quite invisibly via the (developer) services they provide, whilst others, such as Google, can't make them pay without intruding on the experience the user gets (perhaps via an intermediary developer). Yahoo!'s Pipes may have the same issues regarding encouraging flow around their sources of revenue, although at present there's no obvious mechanism for showing them the money.