I'm not sure but I think only they do the "investing/shorting"...

I'm not sure but I think only they do the "investing/shorting" for themselves. From their website

We are investors. We are biased. So are other investors. So are the companies we discuss. So are the banks that raised money for such companies. If you are invested (either long or short) in a company, so are you. Just because we are biased does not mean that we are wrong. We, like everyone else, are entitled to our opinions and to the right to express such opinions in a public forum. We believe that the publication of our opinions and the underlying basis for such opinions is in the public interest.

Don't forget Soren Aandahl - the Head of Glaucus Research - is a lawyer so he knows what he can/can't do.

Mr Aandahl is a former mergers and acquisitions lawyer whose interest in short-selling was first piqued by the Enron scandal of 2001. While studying at Harvard Law School, he worked for the US Justice Department taskforce prosecuting the executives behind the Enron collapse. His time as an M&A lawyer gave him an insight into the art of due diligence.