Players of one of the two games offered on Alibaba Group Holding Ltd's instant messaging service have been finding movies of themselves being posted on China's most popular online video site, a possible setback for the e-commerce giant's attempt to turn its mobile chatting app into a game distributor.

Videos of people playing the charades-like game Feng Kuang Laiwang have appeared on Youku Tudou Inc's website. Many of the estimated 35,000 videos show users in their underwear or naked while playing the game at home with family or friends.

Game developer Hortor Software and game operator Zhejiang Zhile Network Co issued a joint statement on their official Weibo accounts on Tuesday night, apologizing for their failure to notify users that videos of them playing the game would be posted online.