It's the first thing that any new iPhone user has to manually enable. Some users are unaware of how to enable the settings, so they download third-party apps to enable it. My aunt had no idea this feature existed, and was literally amazed when I showed her how to set it up. iPhone Emoji has been emotionally embedded in popular culture. I even know a few people that don't want to switch to non-iDevices because the lack of Emoji (lol). Seems like a bit of a missed opportunity for Apple to not have emoticons enabled by default on all devices. They seem to enable features by default that the majority wants, and I think Emoji is one of them.