When I was in a guild in another game we could display that above our name. In Destiny we had flags that would display our guild motto, symbol etc and if you wanted to join you'd be vetted by the leader. Also the more the members participated in activities the more gear and other rewards we'd get as our guild ranked up. It of course we reset after a certain amount of time and we'd all have to go and do those listed activities to get more gear. Also its was beneficial to do those activities with other guild members cause those perks were higher. idk just thoughts.