I just had a thought Why does Destiny bother to Announce that someone Attunes an artifact? And notice, that the fire in front of the corresponding statue ignites in the process. Could there be a secret to unlock, if in a single lobby, all the artifacts are Attuned at once? I don't have a clan, can't test this myself. Maybe some else would like to test it out.
Why does it say "_____ has found legendary marks"? Could this be a clue for an exotic!?!