Twitter has joined the list of companies making sheepish confessions that it uploads your smartphone's address book when you install its app.

Last week Path made a similar disclosure, which was followed by changes by photo app Instagram to give users more privacy controls. And that led to a bit of discovery by smartphone users themselves that nothing is truly free.

But Twitter, as reported by the Los Angeles Times, seems to be the biggest name to make a revelation so far. The company told the newspaper it is making changes to clarify policy for users of its app. The current policy does not clearly state that Twitter downloads the entire address book of users who use the "Find Friends" feature on the app, including names, email addresses and phone numbers, and stores the data on its servers for 18 months.

"We want to be clear and transparent in our communications with users," Penner wrote in an email to the newspaper. "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. In place of 'Scan your contacts,' we will use 'Upload your contacts' and 'Import your contacts' (in Twitter for iPhone and Twitter for Android, respectively)."

Users who have already had their data uploaded to Twitter's servers can remove their contact databases using the "remove" link in the fine print of the import contacts page on Twitter's Web site, Penner said.

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