If someone is muted, and you do not know that. It looks like he or she is ignoring you, wheter as a random guy or just a friend via /fmsg. It's handy to know someone is muted when you start talking to someone. So if you /fmsg or /msg someone, there will appear a red coloured text. 'This player is currently muted' or so. If you mention his name in a global chat, this will appear too. So no frustration anymore I guess.