Balloons can signify lifting up, letting go, unimaginable joy or simply a birthday wish. When seen by the thousands, they can inspire awe, maybe a little fear, or remind you of a certain classic Pixar.
For Apple, though, balloons are now just another way to add emotion to text messages. In iOS 10, there are a whole bunch of new ways to express yourself in messages (Apple calls it expressive messaging). In addition to drawing doodles, sending heartbeats and taps, each message (between iMessage users, of course) can include effects like bubbles, confetti and, yes, balloons.