Something found - may or may not be dark matter

At work this morning there was a little discussion about the possibility that dark matter had been detected by an experiment in Italy. Cosmic Variance (and now Phil) has the news of a paper (not yet peer reviewed) from the DAMA experiment which is looking for the collision of weakly interacting massive particles (WIMPS).

It would appear that the DAMA folks have a very good detection of an annual modulation to the low energy signal they have been observing. What does that mean? Basically, because the Earth orbits the Sun you would expect it to pass through different densities of dark matter at different times of the year. The signal they observe shows a very convincing yearly variation. That doesn't appear to be under dispute.

What most people seem to be hesitant about is the claim that this is dark matter. There are other things that it could also be and at the moment I'm not clear if this particular experiment can distinguish between those possibilities. So, in summary, this is a detection of something; it could be dark matter but it could also be something else. Whatever it is, it looks interesting. As I find out more about this I'll add updates.