Orion, a member at SEW forums, has decided to allow some of the SEW Forum members participate in an experiment named "Online Discovery of Secondary Terms Associated to a Theme Experiment". The thread named Call for five SEOs, is where Orion explains the study and asks for 5 volunteer SEOs to submit a keyword phrase that meets the experiments guidelines. I am pretty sure all the slots are filled, but maybe he can squeeze in a few.
Orion explains, this experiment pretends to discover secondary keywords associated to a theme represented by an initial key phrase.
Two keywords need to be submitted that have a c-index of 25 points or higher. If your interested check out the thread here.