In ethics, two things are incommensurable if they cannot be compared against a common standard. (In philosophy of science it means something a little different.) For some philosophers (like Elizabeth Anderson) and legal theorists (like Margaret Radin and Cass Sunstein), incommensurability is an important concept because it suggests that there are fundamentally different goods, in both the economic and the ethical senses of the word. That means that goods cannot always be valued on a single metric such as, oh, cash. If (like me) you’re interested in the way that things like human blood and organs are exchanged, this is an important issue. Same goes for lots of other services and items, from friendship to housework.
There’s a lot more to the concept. For instance, goods that are incommensurable are not necessarily incomparable. Item A can be better than item B without being x number of units better. People make decisions like that all the time, and how they do it is a sociologically interesting process. Making comparable is often the first step to making commensurable, and hence making a market. Wendy Espeland is doing some very interesting work on this question right now.
I’m really only bringing all of this up to tell you about whatsbetter?com. What’s better—- M.I. Hummel figurines or Monkey? Ayatollah Khamenei or a cat on a turntable? Winston Churchill or the A-Team Van? How can you refuse to choose? It’s not every day you get confronted with some of the stranger parts of the consistent, transitive preference schedule that economists promise is revealed by your decisions. And you get the see the overall ranking that emerges from everyone else’s choices. This site is already showing early signs of jumping the shark (in a cheesy Natalie Portman vs other random ingenue way), so get there before they start accepting banner ads for porn sites.