Code:
mob/verb/Guild_Info()
set category="Guild"
usr<<"<b>Guilds"
for(var/T in guilds)
for(var/mob/players/P in world)
if(P.key)
usr<<"<font face=tahoma><b>[T]"
var/online=0
for(var/mob/players/M in world)
if(M.guild==T)
online+=1
if(T == usr.guild)
usr<<"<b><small>You have [online] members in your guild"
So, if guilds is a list with guilds, you will get the guild's name for every mob/players with a client in world...
If mob/player is your usual client.mob it will tell you the guild players-in-world times.
Now it should work ^^