I think the most obvious answer is that we are vanguards, or at least we will become vanguards. In the mail sack from 4/26, Bungie says says "It’s incredibly important to us that seasoned Vanguards will find plenty of fun and rewarding things to do with other players who might not be able to commit the same amount of time to Destiny, or who may be just starting out on their adventures." We already know from "Pathways Out of Darkness" that we each enter the world of Destiny as Guardians of the City. Continuing to call us Guardians after we leave the city to take the offense, though, seems silly. After we leave our defensive posts, we're not protecting; we're pioneering. I think "Vanguard" is the perfect classification for those citizens of the last city who leave the safety of the city walls to explore relics of humanity on our world and beyond. Because Bungie capitalizes the 'V' of "Vanguard," I assume it is more than a simple adjective. Graduating from Guardian to Vanguard may not be a trivial task, especially if you must produce your own transportation (read: spaceships). "Waiting for more information from the Vanguards" seems to me like a cute way to say "We're not ready to reveal these bits of the game yet," by referring to those players/NPCs who would be able to report on what is out there in the world of Destiny. Annnd for some very loosely founded speculation, I could imagine a system by which Bungie first tells us the story of Destiny by introducing us to one planet at a time, perhaps allowing us to unlock them as we go, maybe even in the order we choose. Like in many traditional MMOs, we could all begin in some common starting location and gradually blaze unique, non-linear trails toward weapons, gear, vehicles, riches, reputation, and increasingly tantalizing mysteries. EDIT: From the recent "Welcome to the Frontier" release: "For centuries we've huddled under the safety of the Traveler, protected from our enemies. Now, a new era has begun, and the only hope for our future lies in unlocking the greatest mysteries of our past." And "You are taking this mantle just as a new day dawns. Titans, Hunters, and Warlocks have finally returned to our long-lost worlds, only to find out we are not alone."