But Wei believes online education is more than a simple online course. "When students come to the learning center, teaching supervisors arrange the schedule and chart their learning progress. Online and offline are cohesively intertwined," Wei said.

"It's like going to the gym. Some are fine with self-training; others need a trainer. Some are more social, and can learn within a pair or group; others are more independent, so they only need the Internet access at home."

China's three Internet giants－Baidu Inc, Alibaba Group Holding Ltd and Tencent Holdings Ltd－have all made major investments in online education since 2014.

In September last year, SmartStudy.com announced that Baidu had invested $10.6 million in its A round of financing, putting SmartStudy's estimated value at $100 million, a record for an online education startup in China.

Alibaba has opened its own online education platform, Xue.taobao.com. Taobao students can watch live courses or videos with their own accounts.

One of the most popular courses is a Keynote skill course taught by Xu Cen. It now has more than 100,000 hits online.

"Online learning is really convenient, but putting videos of traditional classes on the Web is common and should not be called online education," he said.

Xu majored in recording and film-making in college, and has many skills that other Internet tutors lack. His courses are like movies－with a rhythm and a storyline.

"Online courses require better presentation. Only courses with quality content, good presentation and excellent promotion are received well," Xu said.

Unlike students in a traditional class, online pupils will stop learning at any time if they become tired of a course. Xu is proud of his course quality. A recently released guitar program sold 1,000 copies on the first day.

More Chinese want to learn practical skills like cooking and car maintenance, and prefer more flexible online learning over traditional study.

"Many laymen investors are now eyeing the education industry, but online education is quite unlike the e-commerce of a decade ago," Wei said. "The latter is a trade platform and the former is a vertical field. It's a challenge to change people's learning habits."

Despite the growing demand, many online schools find it hard to recruit students. One big problem is that online education lacks innovative or original content, leading to piracy. Xu turned to Taobao for help to combat the piracy of his courses, but received no satisfactory answers.

The lack of tutors is also a bottleneck. Xu wants to gather as many good tutors as possible and produce only quality courses.

Wei values teaching and research as the core of developing online education, but "better Internet technology and product design would add color to facts and better present quality teaching materials".

"The biggest difference between the online and traditional courses is the former is an interactive learning process based on quality content, research and behavior analysis," Wei said.

SmartStudy.com spends 30 percent of its resources on research and development. And a wearable device to assist online learning could be a reality in the next two years.

"For instance, if you put on a helmet, two people in different regions can communicate. If you are in Beijing, you would see a teacher in Los Angles writing on a board," Wei said.

"Not every Chinese person finds online education their cup of tea, but more are showing enthusiasm," Wei added.