Well, I suppose 3 that generally support it should do. I mean the problem with using buyers is that the system is still young and there are still bugs with them. For example, we have seen several people accidentally list that they are buying for x amount when they are actually selling. Another big problem is that unlike seller trades, buyer trades aren't closing automatically after the trade is complete. Sometimes people just forget to close them if they aren't selling.

Just lots and lots of ways in which a classifieds listing could be invalid. We'd like to see multiple buyers to be confident that what we're seeing is "real."