Virginia Postrel had a really nice post yesterday about how the same good can have different values across time. In this case it’s Diet Coke, and dimensions of differentiation are packaging and temperature, which led Virginia to pay different prices for what, as she calls them, the technocratic economist would perceive as the same good.
An excellent read.
BTW, I finally tried the Diet Coke with Splenda, on the way back from biking in Wisconsin. Tastes more like Tab than the Diet Coke with aspartame. You get more of the spice notes that you expect in a cola. I liked it! And no aspartame aftertaste.