Snapchat may soon allow you to tag people in snaps and stories

The menu that will show up after you tap on a tag inside a post
You'll be able to tag people inside your snaps and stories by typing @, then writing their name, but keep in mind that the autofill option is not available yet, which means you'll have to remember your friend's username and write it manually. The tag is not static though – tapping on it will open a menu where you'll be able to send a friend request or message to the tagged user. Also, whoever gets tagged will receive a notification, so nothing will remain unseen.
source: @nyactor via MSPoweruser