There's more data coming through than is physically possible for Mars researchers to sift through for themselves, and even the keen eyes of a trained scientist might miss a thing or two. Thus, having more eyes to go through the bounty of information would be a great boon to researchers.
So, what is it that you can do to help? Well, take a look around Google Mars. See anything that interests you? An out-of-place shadow, some interesting sediment patterns? What you can do is suggest anything that catches your eye to researchers along the orbital track of THEMIS after registering with the project. With this free registry comes your own profile where other users can see your suggestions—and which ones were taken up by THEMIS researchers to be photographed.
There's a limit to your involvement, with a maximum of ten suggestions per week per person. Also, only visual wavelength suggestions can be made for THEMIS, which has a higher resolution than the infrared instrument anyway.