What Makes Certain Friends on Facebook Appear at the Top of the Friends List?

Facebook doesn't reveal exactly how it calculates which contacts should appear at the top of your friends list, but it is based on your interactions with them. These interactions might include private messages, wall posts, likes and comments, as well as photos or statuses you are tagged in together. The list changes dynamically as you interact with different people over time.

It's not possible to alter the people who appear at the top of your friends list automatically, other than interacting with them more regularly on Facebook. The More Friends section includes other online contacts you can interact with, and you can also use the search box to bring up a particular friend to chat with.

Facebook enables you to set a specific list of friends to appear in the Chat sidebar if you don't want to use the site's automatic ranking system. Click the small gear icon below the sidebar, choose "Advanced settings," and then turn chat off for all of your contacts except a specific group of users. Alternatively, turn chat on for all your contacts, but block a particular set of your friends from contacting you.

Click on any contact listed in the Chat sidebar to send a message. Friends who are online appear with a green dot by their name; friends who have the Facebook app installed on their cell phone or tablet have a mobile phone symbol by their name. If no dot or symbol appears, the friend is offline and chat messages are sent to the user's inbox for reading later.