"Engage. Online behavior always improves when responsible adults are present."

"In the process of upgrading some of the software which publishes our site, we inadvertently started to show you "most shared" on story pages as well as the front page."

Despite the concerns, Mr Zuckerberg predicted that in a few years’ time thousands of websites and services would be linked to consumers’ profiles and preferences, following the trend that Facebook has started.

People would share more information and expect to see services, advertising and websites that were targeted at them, he said. “Things are going to be designed around people,” he added.