BEIJING - The innocent charm of a talking robot proved irresistible to many - but what they talked about proved too much for the automated servant.

An online chatting robot named Xiaotu on the website of Tsinghua University's library had to suspend services during the winter vacation because too many visitors wanted to talk to it about weird and wonderful matters unrelated to library services.

Xiaotu, which means "little library" in Chinese, has the ability to learn during its conversations with humans, but its designers said it has picked up too much "unsuitable material" from visitors to the website.

"It had been a long time anyway since we last cleared up its database, so we decided to suspend the service to do it," said a design group member surnamed Yao, who works in the university's library.

Xiaotu's main functions include answering questions about the library, searching library collections and other search engines, and self-learning.

Design work on Xiaotu started in 2009 and by the end of 2010 it was put online on the homepage of Tsinghua University's library and on renren.com, a social network similar to Facebook.

On the library's homepage, it was scoring more than 1,000 visits a day.

But many of the questions were not pertinent to Xiaotu's role and it learned a lot of language from users which was unrelated to library affairs, and which was often meaningless or worse.

One user asked Xiaotu "Who are you parents?" and it answered "Tsinghua University and Peking University".

But last week, when students returned for the spring semester, Xiaotu was put back into service after its data cleanup.

"We have improved its services and I hope users can teach it useful information now," said Yao.

He added that Xiaotu's filtering ability will be strengthened by increasing its database of sensitive words.