Here is a much better explanation, from the Washington Post, of the research that shows the cat-SARS link:
The long-sought discovery came when a team of researchers from the University of Hong Kong and the Chinese government tested 25 animals from eight species being sold at a live animal market in the province of Guangdong, where the disease first emerged.
The tests found a virus that appeared virtually identical to the SARS virus in saliva and feces of six catlike animals, known as masked palm civets. The researchers directly isolated virus from four of the animals and found pieces of genetic material from the microbe in two others. Tests also showed genetic evidence of the virus in feces of another animal, known as a raccoon dog, and an eighth animal, a Chinese ferret badger, had antibodies to the virus in its blood. None of the animals was sick. A detailed genetic analysis of the virus isolated from the animals found it was identical to the SARS virus from human patients except that it lacked one sequence. The missing genetic material carries instructions for the production of a small protein, known as a peptide, and may have been the change that allowed the virus to jump to humans and then spread readily, Stohr said.