the new recommendation system used to give characters an additional xp rate bonus. it's a system based on recommendations, which are like points. trade your recommendation points with others to increase each other's recommendation level and boost character xp rate. i dont think you get bonus xp anymore, so its just to make your nickname blue in my opinion.
i think the blue name dont increase the xp now... i'm seeing in path notes but i dont see anything about this system and any changes.
source - goddess of destruction patch notes the previous recommendation system changes happened in freya and you can read some info about that here regards.
