Social-networking sites such as Facebook are eroding their members' privacy in the interests of their business model, according to BT's chief security technology officer Bruce Schneier.
The security expert said on Tuesday that social-networking sites deliberately encourage people to disclose personal details about themselves so the sites will have content to sell to advertisers.
"These CEOs are deliberately killing privacy — it's their market — and Facebook is the worst offender," Schneier told reporters at RSA Conference Europe in London. "In the end, Facebook will do its best by its customers, who aren't you [but advertisers]."
Schneier added that people "shouldn't be surprised" that a service paid for by third parties is acting in the interests of those third parties.
Earlier in the day, the security expert said in a conference keynote speech that many social-networking sites only give limited options for privacy. For example, Facebook does not make it easy to delete posts, and those posts are shared with a wide variety of people, Schneier noted.
He told the press conference that organisations are collecting increasing amounts of data on people, to the detriment of privacy. While technical solutions implemented by ISPs would go some way to improving internet privacy, governments should ultimately shoulder the responsibility, he said. "I would like to see governments pass broad data-protection laws," Schneier added.
Facebook responded on Wednesday by saying that while its business model is to sell to advertisers, its focus is on its users' experience.
"Advertising is Facebook's business model, but nothing is more important to us than user experience, safety and enjoyment," it said in a statement. "In a more connected world, advertisers are social too. This gives you the chance to connect to the companies and brands you like and learn more about their products and services."
The social-networking company said that it does not share personally identifiable information with advertisers or sell personal information. Advertisers only ever see anonymised and aggregated data, it added.
In addition, Facebook members own and control their own data on the site, the company said.
"Users control and own all of their data on Facebook and this is clearly set out in our terms," said Facebook. "Users control when to add information to Facebook, when to change it and when to take it down. This is not affected by any third party."