After first quietly experimenting with tags back in November, Amazon lately has added a couple of interesting new wrinkles. In some listings, you can also view what other tags customers applied to the item, as well as see which customers did the tagging.

That last suggests some interesting possibilities--namely, the potential for spontaneous communities to emerge from folks who share the same interests. Amazon already has the capability to add another customer to "Amazon Friend" and "Favorite People" lists. In fact, as I poke around some more, I see these are now part of a "Your Amazon Home" page where you can set up your profile, upload a photo of yourself, and share your purchase info with others.

The company's just testing the new tagging features for now (isn't everything on the Web just a test?). But it'll be interesting to see if Amazon can spice up its matching algorithms with the secret sauce of Web 2.0: real, live communities on its site.

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