Facebook, LinkedIn and other social networking sites represent "one of several threats" to the future of the world wide web, its founder, Sir Tim Berners-Lee, has warned.

Some of its "most successful inhabitants", such as Facebook and big telecommunications companies, had begun to "chip away" at its founding principles, Sir Tim wrote in a Scientific American essay published this week.

Social networking sites that do not allow users to extract the information they put into them is a "problem" that could mean the web is "broken into fragmented islands", he said. Google accused Facebook this month of leaving its more than 500 million users in a "data dead-end" with their contact details and personal information "effectively trapped".

Although Facebook, the world's most popular social network, recently began allowing users to download profile information, including status updates and photos, it has been roundly criticised for leaving users' networks of contacts "walled" inside its own site.

Sir Tim warned that such a "closed silo of content" risked leaving the web fragmented.

"The web evolved into a powerful, ubiquitous tool because it was built on egalitarian principles," he said. "The web as we know it, however, is being threatened in different ways...

"The more you enter, the more you become locked in. Your social networking site becomes a central platform - a closed silo of content, and one that does not give you full control over your information in it."

Sir Tim said there was a worry Facebook could become "so big that it becomes a monopoly, which tends to limit innovation".

Source: smh.com.au