This is a good question. Google have just realised a new service called Latitude. Latitude lets smartphone and laptop users share their location with friends and allows those friends to share their locations in return. Although not pinpoint accurate, Latitude can display your general location based on information from GPS satellites and cell towers. Latitude works on both mobile devices and personal computers.

From a privacy perspective, it is an opt-in service (i.e. you have to ask to get it, it is not provided automatically without asking your permission first) which is good. It also gives a choice of levels of visibility. However the privacy concerns are similar to that as with the increasing practice of tracking mobile phones today. Apart from the obvious risks to privacy, e.g. everyone getting to know where everyone is, that is if you care, and Google holding more information than what they have promised, finally providing yet another vector for surveillance by government authorities. There is the concern for the privacy and safety of children. 

It risks in fact becoming quite a fashionable thing to do amongst young people, and in just 5 years we may even forget how life was without this service. Children today will be sharing their location information with their friends, and if they are unable to determine the difference between online friends and real friends the risk of physical sexual exploitation is higher than what it is today.

Children are easily befriended online. If they agree to share their location information with someone that has befriended them, and has in fact intentions to groom them. The online grooming process (this is described in the book “Virtual Shadows”) is speeded up significantly. It will give the predator the child’s movement data to help them to build up a profile of the victim.  Latitude will in effect become yet another tool in the existing toolkit used by online predators to groom any individual child ready for sexual abuse.

Following is a clip from google explaining the privacy features of the service.