Up until today, when you wanted to take a friend in a status update, you’d have to use the "@" symbol and publish their entire name in the update.
Facebook enhanced this feature so that you don’t need the "@" symbol, or your friends full name.
Tagging your friend’s with the "@" symbol
When you type your friend’s name in an update, Facebook will auto-complete the name. Simply select the name and your done.
Tag your friend’s without mentioning their full name
If you want to tag your friend without mentioning their last name, simply tag them, then simply delete their last name.