I started this thread over in CC, where it belongs, but it contains an interesting study that may be possible:
I believe that there is a measurable difference in the use of the reputation icon since the forum upgrade, possibly restricted to new users, but possibly across all users. There is rarely a chance to measure the difference an icon makes, but the more I think about it, this forum now has a chance to mine its database to see something really interesting to programmers. If there has been a noticeable drop in repping coincident to the inseption of the new forum software, I would say that it would be empirical evidence of the impact that icon design has on UI design. Such a study would be pretty hard to do in most cases as the sample size would be low and could easily be biased. However, with the large number of users of this site, sample size would not be an issue. Therefore, let me add a request that somebody take a look at this in the interest of GUI design.