Posted on the walls are typically guild leves, but I was thinking that this would be a good way to advertise linkshells as well.

Perhaps have a wall posting, or counter, or something that people could register there linkshells with. Once registered they can place a one sentence description of their group and whether the group is open for invite.

If it is open for invite perhaps also display everyone holding a pearlsack for that guild (and whether or not they are currently online) so that someone interested could /tell the people needed to join.

This would probably be super helpful for people wanting to find like an rp guild, or a guild that focused on endgame stuffs, etc without needing to go to an outside source. (I.e. a website off the game).