Founded in Chengdu, Sichuan province, Manyoujing now has more than 2 million registered users.

Founder Wang Long said in an interview with technology media website 36kr that 70 percent of its users are both buyers and sellers, and 90 percent of the books that are collected can be sold in 30 days.

"We have noticed a demand among young people for reading by exchange - to read more books without paying more money" Wang said.

In addition to Duozhuayu and Manyoujing, there are customer-to-customer online platforms for used books such as Confucius and the flea market platforms Xianyu and Zhuanzhuan.

Confucius, founded in 2002, is now one of the largest online used-book platforms and features old titles that are worth collecting. It has attracted more than 10,000 bookstores and over 30,000 booksellers.

In Beijing, secondhand bookstores are no longer easy to find, as young people prefer to strike deals online. Used books offline can be found at the Panjiayuan Antique Market each weekend and at the book fair in Temple of Earth park, which is held several times a week.

According to a report on Chinese reading habits last year, released by Alibaba in January, reselling used books and also giving them away, boomed on Xianyu. People in Guangdong province topped the list for traded or giveaway books, with 1.59 books per person on average, followed by Shanghai residents with 1.11 books and those in Beijing with 1.08.