Sina-Weibo ( SINA): Sina started out as a news aggregator and search engine before adding Weibo, which means micro-blog in Chinese and has become as essential to China as Facebook ( FB) has in the West. It was already one of the top three search engines-slash-aggregators 10 years ago. Every day or two back then you would meet someone new with a sina.com e-mail address. Now the government blocks Facebook, among other Western social media, and encourages local alternatives that it can censor. Facebook's loss of China raises Sina's essentialness. The Nasdaq-listed Sina reported revenue of $483 million in 2011, about twice what it took in five years earlier. Its share price was little changed last year. At the time of publication the author had no position in any of the stocks mentioned.Follow @ChinaWatchRalphThis article was written by an independent contributor, separate from TheStreet's regular news coverage.