The closure of two popular subtitle and video sharing websites reflects a hardening of attitudes toward copyright violation, but more proactive measures are needed, experts say.

Fans of foreign TV series who visited yyets.com and shooter.cn for free downloads and translated Chinese subtitles found the sites were shut on Saturday. Both carried statements about the closure on their home pages.

"Our website is cleaning up (pirated) content," said the yyets.com statement. "Thanks for users' attention and support. Since (being) established by a group of overseas students in 2004, we have ... offered subtitle translation for popular foreign TV series, only hoping to help Chinese viewers."