Snapchat Emoji, Icon Meanings: Yellow and Red Hearts, Sunglasses
http://www.newsweek.com/snapchat-emojis-icons-meaning-friends-heart-yellow-red-sunglasses-949968
In the world of Snapchat, emojis indicate who is friends with whom and how strong that friendship is. The emoji—or emojis—that appears next to users' and their friends' names in the app can tell them whether it’s someone's birthday, whether they have a Snapchat streak in the app and even if they share a best friend.
The emojis can change quickly depending on who snaps whom and when. A combination of them can appear next to anyone’s name in the app. Users can also customize their Friend Emojis in the app. Some users also have their zodiac sign next to their names in the app based on their birthday.