Each Instagram Direct photo is processed just like a regular Instagram (cropping, filters, caption), but the next step allows you to specify exactly who will see the image. Send one image to just one person, or share it with a variety of friends.
Below: We snapped a photo of a T-shirt souvenir we'd just bought, to share with some of our Instagram friends. As each addressee opens the image, you receive an alert that it's been viewed. Any comments on the image are also seen by all looped in on the message.
Since Twitter DMing can be clunky and Snapchat has a bad reputation, Instagram Direct may quickly become the leader in private photo sharing. This is especially important for travelers needing to communicate on a group trip, or who want to share an experience without broadcasting it to the whole world.
Example 1: Four friends travel to Rio for Carnevale. On days they aren't experiencing the city together, Instagram Direct photos can serve as a conversation of individual experiences, to discuss later on when they perhaps reunite for dinner.
Example 2: A couple heads to wine tastings in Napa, relying on recommendations from friends. They may choose to share snaps of their favorite wines and vistas by sending Instagram Direct messages only to those friends who've previously been to Napa or have interest in going. This keeps their public feed from being too cutesy, and too annoyingly Napa-braggy.
Example 3: A family vacation with young children means mom and dad can send Instagram Direct messages to just their family members on Instagram, while still utilizing the fun filters and ease of it all.
Just one note of advice: as with any social media service, don't go overboard. Constant messaging gets old quickly, and any extremely sensitive material should be kept wholly private just in case of app flaws. Use common sense, and follow @Jaunted on Instagram, of course.