FBI plans social network map alert mash-up application
The London-based campaign group, Privacy International, said it was worried about the consequences of such activities.
"Social networks are about connecting people with other people - if one person is the target of police monitoring, there will be a dragnet effect in which dozens, even hundreds, of innocent users also come under surveillance," said Gus Hosein, the group's executive director.
"It is not necessarily the case that the more information law enforcement officers have, the safer we will be.
"Police may well find themselves overwhelmed by a flood of personal information, information that is precious to those it concerns but useless for the purposes of crime prevention."