From the surveillance entertainment of Big Brother to CCTV and celebrity magazines, the boundaries of what is regarded as appropriate to put in the public domain are shifting dramatically. But nothing is challenging our notion of privacy more than social networking, with 26 million of us using Facebook to share the minutiae of our lives every month in the UK alone.
Facebook has proved irresistible to many because we are lured into joining by friends and family. Browsing, reading, comparing and nosing is instinctive, impulsive and reflects our tendencies offline, our "social graph", as Facebook founder Mark Zuckerberg likes to call it. Having executed the social networking business idea better than its rivals – MySpace, Bebo, Friendster and Hi5 have been left for dust – Facebook has seen astonishing growth, from a Harvard dorm project in 2003 to a global phenomenon that had 500 million monthly users by July this year. That's already one in 13 people on Earth, and Zuckerberg recently predicted it was "almost a guarantee" that his site would reach 1 billion users, with growth in relatively untapped markets such as Russia, Japan and Korea "doubling every six months".
On Thursday, Facebook unveiled its latest gambit in the battle to remain top of the social networking heap with a move into geolocation services, which harness the GPS functionality of increasingly powerful mobile smartphones. Facebook Places will launch first in the US and later in the UK, allowing users, if they choose, to share their location with friends on the site by checking into public venues. Sensitive to intense public scrutiny of its privacy controls, Facebook was careful to make the service opt-in but every geolocation service – including Google's