There's an App for that

“I’m really terrible about remembering to store numbers in my phone,” says Delta’s International Editor Molly Quell, “so I’m constantly getting phone calls from numbers I don’t recognize.” A friend told her about an app called Truecaller, which calls itself a “global dynamic directory for mobile phones.” The app uses existing directories and phone books shared by users to identify unknown numbers. If a number not in your contacts list calls your phone, Truecaller will search their database for a match and, if one exists, give you the name of the person or company calling you. You can use the app to block numbers and has reverse number lookup functionality as well.