Google's Orkut social-networking site has introduced a 'safety filter' that automatically filters out adult content such as sexually suggestive phrases or images.

The filter has been introduced in India, and is turned on by default for Orkut users in the country. Rahul Kulkarni, product manager at Google India, said Google plans to introduce it in other countries in the next few weeks.

The new Orkut filter screens for content that may not violate Orkut's community standards for objectionable content, but which users may not want to see, Kulkarni said.

Google Orkut has added the filter because there is always a grey area as to what is considered as unacceptable adult content, which is likely to vary from country to country or from one household to another, Kulkarni said.

Users have the option to turn off the filter, Kulkarni added.

With the 'safety filter' on, if users come across content such as photos or text that they may find unacceptable, they will receive a warning and the specific content will be replaced by special icons, according to a post yesterday on the Orkut blog.

No filter is fully accurate, so if users see a page that they think should be blocked, they have to flag it as usual and let Orkut know, according to the blog.

Orkut has been criticised and even sued in India - not for sexually explicit content but for political content, including communities on the site that criticise the country or some of its politicians.

The filter in Orkut is designed to filter sexual content and not political content. Kulkarni noted that filtering political content would be far more difficult, and woudl raise the question of whether this would come in the way of freedom of speech.