Companies use apps to harvest users' personal information But according to a poll, up to 70 per cent of smart phone users never read such terms and conditions, leaving personal information, including text messages, their location and contacts, unwittingly exposed. Emma Draper of the Privacy International campaign group warned: "Your personal information is a precious commodity, and companies will go to great lengths to get their hands on as much of it as possible." Other companies that can access information by those who download apps include Flickr, a photosharing site, Badoo, a dating site, and Yahoo! Messenger chat service. Earlier this month, Twitter acknowledged that it has copied the content of peoples" entire address books from their mobile phones and stored the information on its servers, without many of its users realising. As a result of this practice coming under scrutiny, the San Francisco-based microblogging company promised to update its privacy settings to ensure it is more explicit about what personal data people are sharing when using Twitter on their smartphones. Facebook was criticised last year after making changes to its developer terms which meant users may have had to share their phone number and address in order to access a third party application.