Posting an update to Instagram doesn't have to mean sharing your life with every single person you've befriended there. In fact, all of the major social apps give you more granular control than you might realize. If you want to set up a private, select group of people to show off photos of your baby to—or to keep your most raucous nights out a secret from—you can do so without resorting to emails or group chats.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.