Facebook friends chat list?

[chadweiser]

on my facebook page when logged in. on the right side of the page it has a list of some of my friends some so logged in with the green dot then some have the square with 1m or 2h which im assuming means 1 minute or 2hours. whats that mean? how do i get my friends to see i was last on without dissapearing from the list?

[Sean]

It's automatically done by Facebook. They will see once you fully disconnect how long it's been. (Vice-versa)