Why do people tag other people in Facebook comments?

[Daniel]

I "like" several pages that post funny images, and in some of the comments, I see people that don't really comment, they just tag another person's name as a comment and nothing else. So why do people do this? It seems irrelevant to whatever the image may be. And the person tagged in the comment usually doesn't have anything to do with the comments to begin with.

[abraXus]

they do it so that person will get a notification pointing them to that post, so they will see it too