That might not sound very important, but Shanghai operates under a government-organized auction system to distribute plates. Last year, they were selling for as much as $15,000, according to Car News China. The measure is a way to control the number of cars on the road, which contribute to the city's bad traffic and poor air quality.
Electric cars are exempt from the auctions and get a free license plate. However, that rule only covers Chinese-made electric cars. Obviously, Tesla doesn't build cars there (at least for now). But the Shanghai government will exempt 3,000 foreign electric cars per automaker to receive free plates, according to CNC. After they are gone, the company would have to go back and ask for more.
Tesla confirmed the plan to Autoblog and pointed out there was a small blurb about it in the automaker's Q1 2014 financial release: "Model S drivers in the city will be entitled to free license plates, thereby avoiding the usual public auction price of $10,000 to $15,000 per plate." It certainly seems like a great enticement to grab early buyers for the Model S there.