These Internet services pop up on millions of PCs and smartphones every day, selling goods, processing searches and offering the latest in celebrity gossip. But if you're not Chinese, you probably won't recognize their names; they're catering to the giant population of China, and prospering from legions of loyal users.
With an online population of more than 600 million, China is one of the world's most important markets for technology companies, but U.S. firms like Google and eBay have struggled to make it big. Here are six of the top Internet companies in China.
Qihoo 360: Baidu gets all the attention when people talk about China's search market, but Qihoo 360 is chipping away at Baidu's lead. The company is best known for its online security software, which has more than 400 million users, but in 2012 it launched a search engine that now has close to a quarter of the Chinese market.
The company has been embroiled in controversy, however. It had a public feud with Baidu, which accused it of indexing its pages without permission, and it's had nasty disputes with Tencent, one of China's better known online giants. None of that has done much to slow it down, though.
JD.com: Try to come up with a Chinese e-commerce company not called Alibaba and you might struggle, but JD.com has made its mark as an online retailer that operates in a similar way to Amazon.com. Formerly known as 360Buy, JD.com has more than 140 million users who are lured in by its fast delivery times. Customers in Beijing who place an order before 11 a.m. can receive it the same day for free.
JD.com is starting to expand outside China. It now has an English-language site that offers free global shipping for goods over US$49, but don't expect packages to arrive the same day; turnaround time is usually at least a week.
Jiayuan.com: It's not easy to find a date in China; the country's one-child policy has created a gender gap in the population that's skewed toward males. At the same time, women in their late 20s are tormented by press coverage about "leftover women." Enter Jiayuan.com, one of the country's oldest and best known dating sites with 100 million users. Jiayuan means "beautiful destiny" and the site is tailored to users looking for marriage. Earlier this week, the company said it would launch its dating site in other countries.
Netease: The company's main site, at 163.com, is the 15th most visited site in the world according to the Alexa Internet rankings, right behind LinkedIn. 163.com is a major news portal for China, and Netease also claims to operate the country's largest email service, with more than 590 million users across its various domains. Like other tech giants in China, Netease also offers search, online video and social networking. But its real money maker is online games. Some of the most popular are fantasy games it develops itself, but Netease also distributes U.S. titles like "Starcraft II" and "Diablo III."
Tianya.cn: Before China got social networking sites it had Tianya, a BBS discussion forum that launched in 1999. The site remains popular and Tianya estimates it has 200 million monthly users. While China is notorious for censorship, there's an abundance of local news about sex, crime and hypocrisy that Chinese people love to gossip about.
In some cases, Tianya and other Chinese forums like Mop.com are a platform for mass action. In 2006, the forums helped reveal the identity of a woman who was seen brutally killing a kitten in an online video. They're also used for so-called "human flesh searches" in which users band together to identify perpetrators of perceived injustices. The crusades have helped expose fraud and corruption, but they can also turn China's Internet users into a virtual lynch mob.
58.com: If you're looking for housing, a car or just trying to sell something, try 58.com, which is basically China's version of Craigslist. The site covers 380 cities and has close to 130 million monthly users who post jobs, special offers and personal ads. Unlike Craigslist, 58.com is listed on the New York Stock Exchange, part of a wave of Chinese tech companies selling shares in the U.S.
They all have room to grow. On Thursday, the China Internet Network Information Center said China has 618 million Internet users. That puts the nation's Internet penetration at 46 percent, with millions in its rural areas still to come online.
This story, "The hottest Chinese Internet firms you've never heard of" was originally published by IDG News Service .