Burglars are cashing in on posts on sites like Facebook to see when homes are empty and find out if valuable items are in them, prompting police to urge caution when revealing information online.
Risky updates include "checking in", posting photos when on a family holiday, or sharing pictures of expensive gadgets and other purchases, police said.
Today's warning comes as new research revealed nine out of 10 young people aged 16 to 21 share information on social networking sites which could put their family home at risk.
According to the research by security firm ADT, more than half (56%) post their location or movements on social media at least once a week; 81% upload photos of themselves and friends when out and about; 48% share pictures of things they have just bought; and 29% highlight locations and places to meet.
The figures come from a survey of 1,018 young people aged 16 to 21 carried out online between June 11 and 17 by Crowd DNA on behalf of ADT.
Assistant Chief Constable Gareth Morgan, spokesman on burglary for the Association of Chief Police Officers, said: "Social networking has become a part of everyday life.
"Unfortunately there are some individuals who use it as a means of gathering information to commit crime.
"Users of social networking sites need to be aware of this and use caution when telling people where they are, or posting messages about valuables on their possession or in their homes."
Mark Shaw, from ADT, added: "While checking in at the airport might be a great way of letting friends and family know you're off on holiday, you're also informing criminals that the house is empty and an easy target.
"Teenagers in particular have grown up with Facebook tracking their every move and see nothing wrong with sharing information online that you'd never dream about passing on to a stranger on the street."