Announced at Apple’s Worldwide Developer Conference on June 6, 2011, iMessage lifted the iPhone away from a reliance on SMS text messages and allowed Apple to innovate in the messaging space. It also allowed Apple to engineer a soft lock-in within its community through those same messages.

This is Day 14 of 30 Days of iPhone, a look at the moments that shaped the smartphone era .

Security, Encryption, and the Origins of the iPhone’s Blue Bubble

One of the iPhone’s key pillars was iMessage, especially its encrypted messages. Keeping user data safe became more prominent in every iteration of the iPhone and iOS, and iOS5’s iMessage was no exception. Apple could now extend messaging to include features more commonly seen in email, such as delivery receipts and typing indicators that let you know someone else was composing a message.

Just as FaceTime before it, iMessage launched as running exclusively on Apple hardware. It wasn’t a complete lock-in; iPhones could still send and receive SMS messages inside iMessage. Apple provided a visual clue for the message’s origin: blue meant a secure iPhone message, while green meant an SMS message of 140 characters sent in the clear. This distinct color divide quickly became a powerful cultural shorthand among mobile users.

Building The iPhone Ecosystem and Apple’s Modern Market Dominance

By turning communication into proprietary software, Apple created an ecosystem that encouraged users to stay with Apple hardware across generations and used peer pressure to bring their communities into Apple’s reach. What started as a simple messaging upgrade in 2011 remains the invisible wall protecting Apple’s modern empire .

This is Day 14 of 30 Days of iPhone. Yesterday, we looked at how Steve Jobs’ death shaped Apple’s corporate direction .