[img_assist|nid=26289|title=|desc=|link=popup|align=left|width=83|height=150]Location-based social network Foursquare has updated its iOS and Android apps, giving users the ability to check in friends as being in the same place.
Adding other users to a location status will send a notification asking them for their permission. It's a one-time process, meaning the user will be able to check that person whenever they want in future without express permission.
That seems likely to lead to some location-based pranks down the line, though the checked-in friend will continue to receive notifications, and be given the option to delete themselves from the status.
The feature is a logical exension of the 'mentions' launched by Foursquare last year, which it says is already being used in 90 per cent of cases to indicate who the person is with.