From the RuneScape Wiki, the wiki for all things RuneScape

An example of the Friends List interface

The Friends List can be used to send private messages to other players, including moderators, and to see which worlds they are currently on. If a player's private chat is set to 'off', then they will always appear as offline and it will not be possible to send them a private message. If their private chat is set to 'friends', then only people on their Friends List will be able to send them private messages.If you do attempt to send a message and as you press enter they log out, it will say this player has left the server

To add a player to the Friends List, click the 'add friend' button in the Friends List interface, type the player's name, and press enter or simply right-click their name in the chat box and selecting 'add friend'.

To delete a player from the Friends List, either right-click their name on the Friends List and click 'remove', or click the 'del friend' button, type their name and press enter. The friends list can hold up to 100 names for free players, and 200 for members.

If a player meets one of his/her friends in-game, the friend's character will be represented by a green dot on the minimap in the upper right corner of the screen, instead of a white dot like most other players.

Some players add "famous" players, such as top people on the high-scores to their friend lists. However, the player has a very little chance to see the top player, because the top player’s friend list is most likely full. Most "famous" players also have their own Private chat set to "Friends", so anyone not on their Friends List will not be able to send them private chat.

The Friends List is not always used for contacting or keeping track of friends. Some players might add another player's name to their Friends List to spy on them, or to locate them on the minimap for a trade opportunity, although this would only be possible if the other player had private chat set to 'on'.

Some players may spam via private chat, so it is useful if one turns their private chat to “friends” or "off".

An update on 8 July 2009 made it impossible to add friends to your friend list that don't exist. All bad names in the list at the time of the update got an asterisk.

Previous versions of the Friends and Ignore List Icons.

An update on 12 November 2009, the divider between both usernames/friends and the status is movable. This is to view the username/friends full name. If the divider was over the usernames/friends, it would show somewhat like this "CutOffName..."

Colours of the names

• Green means the player is online, and in the same world.
• Yellow means the player is online, but in a different world, or in a Funorb game.
• Red means the player is offline, or has their private chat set to "friends" (if you are not on their friends list), or "off".

Trivia

An example of a player who added themselves to their friend's list.

The player at the top's name is yellow, despite being on the same world.

• On the 8th of July, along with the Mobilising Armies update, the friends list icon has an update to its appearance.
• On the 8th of July, along with the Mobilising Armies update, players had the ability to add themselves to both their friends and ignore lists by typing in their username with an added space (EX:"Username_"). It has since been fixed though players who added themselves to their friend's list during the time have not had their name removed.
• If a player had his or her named added to their friends list, they would not be able to access FunOrb games as the server would crash. This could be corrected by logging into RuneScape and deleting their username from their friends list.
• Some players have a glitch where even if someone they added to their friends list is online, it might say they are offline, the added player may still Private Message the glitched player.
• After a update on the 2 September 2009, a friend list glitch occurred, saying to some players that their friend wasn't online when they were and had private chat "on". The cause of this is unknown, however might have something do with self adding, also saying that a friend on the same world is on a different world.