Facebook provides its members with a plethora of different ways to interact. Members can communicate by writing on their own wall (home page), other member's walls, or by simply responding to comments appearing in status updates or live feeds. You can even notify a friend that you made a comment about them on your wall by simply turning the person's name blue. Once the name is blue, it not only posts the comment directly to your friend's personal page, but also creates a clickable link that can take other friends directly to your friend's wall.
Place an "@" in the "What's on your mind?" or "Write Something" box on the Facebook page you are currently on. You may also place an "@" in the comment box if you wish to directly comment to one person in a post that is part of an ongoing conversation.
Type the first letter of the person's first or last name that you want to turn blue. A list of your friend's will appear in a drop down menu.
Click on the person's name that you want to turn blue. This will make the "@" disappear and your friend's name will appear in blue highlight. Submit your finished post and your friend's name will appear blue in the post.
You can only turn a person’s name blue if they are actually on your friend list. If you reply to someone in a conversation that is not a friend, you cannot turn the person’s name blue.