Ethical hacker Ankit Fadia today said social networking sites Twitter and Facebook should be more responsibile and responsive when it comes to removing objectionable content.

He also said it is impossible to control content being posted on Internet, but social networking sites are doing it through post screening measures.

"Using Twitter, Facebook anybody can post what they want.

There should be strong post screening measures available.

Twitter and Facebook should be more responsible and more responsiveness when government gets in touch with them for removing contents that is illegal or hurts sentiments of region or religion," Fadia told reporters here.

Fadia was speaking on sidelines of his book launch 'How to Unblock Everything on the Internet'.

"Any nudity or pornographic material is being removed.

There is always a link on YouTube and Facebook where you can report the content as illegal and it will be taken down. There is no technology available that can look at an image or video and decide whether it is legal or illegal," Fadia said.

He said he does not promote any illegal activity, though his book will guide non-tech savvy students to unblock social networking sites blocked in their instituted.

"I support unblocking of sites that are legal. Most educational institution across the world are not blocking Facebook, not blocking Twitter. In all IITs, major engineering college these websites are blocked which I strongly oppose," he said.

He added that he expects IT system managers in organisations and the government will be among first buyers of the book to make their system more robust and therefore he will come out with new ways on unblocking website within next three months.

"Blocking sites is no answer. People who waste their time will find other ways of wasting their time. There needs to be more dialogue between user and administrator, instead of just policing it," Fadia said.