The address book in smartphones — where some of the user’s most personal data is carried — is free for app developers to take at will, often without the phone owner’s knowledge, The New York Times reports. Companies that make many of the most popular smartphone apps for Apple and Android devices — Twitter, Foursquare and Instagram among them — routinely gather the information in personal address books on the phone and in some cases store it on their own computers. The practice came under scrutiny Wednesday by members of Congress who saw news reports that taking such data was an “industry best practice [1].” Apple, which approves all apps that appear in its iTunes store, addressed the controversy on Wednesday after lawmakers sent the company a letter asking how approved apps were allowed to take address book data without users’ permission…