Beijing promotes Internet use for business and education but bans material deemed subversive or obscene and blocks access to foreign websites run by human rights and Tibet activists and some news outlets. Controls were tightened after social media played a role in protests that brought down governments in Egypt and Tunisia.
In a reminder of the Web's role as a political forum, a group of 70 prominent Chinese scholars and lawyers circulated an online petition this week appealing for free speech, independent courts and for the ruling party to encourage private enterprise.
Xi and others on the party's ruling seven-member Standing Committee have tried to promote an image of themselves as men of the people who care about China's poor majority. They have promised to press ahead with market-oriented reforms and to support entrepreneurs but have given no sign of support for political reform.
Communist leaders who see the Internet as a source of economic growth and better-paid jobs were slow to enforce the same level of control they impose on movies, books and other media, apparently for fear of hurting fledgling entertainment, shopping and other online businesses.
Until recently, Web surfers could post comments online or on microblog services without leaving their names.
That gave ordinary Chinese a unique opportunity to express themselves to a public audience in a society where newspapers, television and other media are state-controlled. The most popular microblog services say they have more than 300 million users and some users have millions of followers reading their comments.
The Internet also has given the public an unusual opportunity to publicize accusations of official misconduct.
A local party official in China's southwest was fired in November after scenes from a videotape of him having sex with a young woman spread quickly on the Internet. Screenshots were uploaded by a former journalist in Beijing, Zhu Ruifeng, to his Hong Kong website, an online clearing house for corruption allegations.