If this theory proves correct, it will mean modern people are descended from something akin to chimp-human hybrids. That is a new idea, and it challenges the prevailing view that hybrids tend to die out.
From the BBC article comes this gem:
A US team says its results hint at the possibility that interbreeding occurred between the two lines for thousands, even millions, of years. This hybridisation would have been important in swapping genes for traits that allowed the emerging species to survive in their environments, explain the scientists affiliated to the Broad Institute of MIT and Harvard and the Harvard Medical School.
I think a lot of this pretty speculative and will wait for the Nature article. It certainly is provacative, however.