Twitter admits to storing contacts of iPhone users

Microblogging site Twitter has admitted that its smartphone app copies the entire contents of a user's address book and stores the data on its servers, often without the knowledge of customers.

Access to the address book is enabled when users click on the 'Find Friends' feature on smartphone the apps.

The practice came to light when an app developer in Singapore, Arun Thampi, noticed that his contacts had been copied from his iPhone address book without his consent by a social network called Path.

According to The BBC, two US congressmen have written to Apple asking why the firm allows the practice on its iPhone, as it contravenes app developer guidelines.

The Los Angeles Times reported that the app uploads every address book contact and stores it for 18 months.

Critics pointed out that that these apps are all available for download from Apple's iTunes store, even though the practice of copying address book contacts without prior consent appears to violate its user guidelines.

Meanwhile, Twitter said it would update its app in the wake of the disclosure, and clarify its privacy policy for users.

"We want to be clear and transparent in our communications with users. Along those lines, in our next app updates, which are coming soon, we are updating the language associated with Find Friends - to be more explicit," Twitter spokeswoman Carolyn Penner said.

Twitter is currently telling its users that it 'may customise their account with information such as a cell phone number for the delivery of SMS messages or their address book so that they can help them find Twitter users they know'.