I have noticed two things about certain player's gamercards/tags in Destiny that I cannot figure out what they are/how to get them. Firstly, I often see people with gamercards/tags (I don't know the correct term) that have a message on them. At first I thought it was from your profile bio, but I added one to mine and it didn't show up. Secondly, when I look at the post-game carnage in the Crucible, I often see letters after some people's names, (usually all-caps). If anyone could explain these things to me that would be great.
EDIT: An example of the 1st question, the second place person has words that say "Warlock Master Race", however I have seen different things.