A mobile phone service which lets users track their friends and family members has been launched in the UK. You can also choose to add a Sniff search application to your Facebook profile.

Brian Levin, the Useful Networks chief executive, stated the service could be utilised only by those people who had first signed up, to accept the terms of the web site. Once a user has signed up, he or she can opt to become ‘invisible’ if the user wishes to drop off the service.

A user can text Sniff to know the location of a friend or a family member and will get a reply message, which shows their location plus a map. The Sniff service works across all mobile networks in the UK.

Brian Levin stated:

The key thing is an explicit opt-in, so you ought to fully accept that you allow yourself to be (traced or) located. We say it is like deciding who you would ask to look after your flat while on holiday, or who you would give the keys to your car.

Useful Networks refuses to reveal how much it has paid to the mobile operators for accessing the location data of users.