Unfortunately, there is no sign or symbol that will signify whether someone in the map is actually "active" or away from the keyboard. Many people may be moving slightly-- running, walking, changing emotes, etc., and talking in the chatbox. These are all signs that someone is active in the game, although you can always send a whisper to someone through the chatbox, in which some may choose to reply. Some people are busy with a group roleplay or tabbing out into other internet browser windows, so it all depends on the person and the map you're sitting in. My advice would just be to chat a bit in the chatbox, and some folks may decide to answer back and join in. c: