This is fairly momentous because China has so far been very determined to wall off its internet from the rest of the world, viewing social networking sites as potential causes of social unrest. The Shanghai free-trade zone is planned to be an area to test out new policies before rolling them out nationally several years later, so this could be seen as the possible motion for more liberal internet access in years to come for the world's rising superpower.
"If [foreigners] can't get onto Facebook or read The New York Times, they may naturally wonder how special the free-trade zone is compared with the rest of China" said an official (according to CNBC)
This could open up a massive new market for social media sites in the future (China has a population of 1,360,070,000 people [wikipedia]) but, while Twitter & Facebook (Facebook shares jumped 4.9% after the news) may begin to consider a possible Chinese strategy, there's still a long way to go. China has recently tightened up its control over microblogs, some of which which have previously exposed massive overspending by officials, in its increased campaign against online "rumormongers". Last week they arrested a 16 year old boy for "disrupting social order" like this.
I have to wander, if this is the Communist Party's view, how much are they really going to like Facebook or Twitter, I'm sure plenty of posts are completely fabricated and they've proved a useful political tool for campaigners in the West?