Cover your eyes, Winklevii: Facebook, the world’s most popular social networking service, has held exploratory talks with potential partners about entering China, a person familiar with the matter tells Bloomberg. “We are currently studying and learning about China, as part of evaluating any possible approaches that could benefit our users, developers and advertisers,” Facebook said in a statement. Facebook currently has over 500 million users, and entering China would not only be an advertising coup, since it’s the world’s second-largest economy, but also the world’s largest Internet market, with 457 million users. Facebook honcho Mark Zuckerberg visited China in December and met with several Internet companies, and back in February, the social network said it had plans to open an office in Hong Kong. China currently blocks sites like Facebook, Twitter, and YouTube due to the country’s strict censorship rules.