Bungie sure dropped lot of information on Destiny: The Taken King, and one slice of it included new information on Vanguard and Crucible marks.
According to what we gleaned from the livestream, Vanguard and Crucible marks are being replaced by a single new currency called Legendary Marks.
These marks are usable account-wide as with Glimmer, and will drop during daily and weekly Heroic and PvP lists. While there will be no limit to the amount of marks earned in a week, your wallet will only hold 200.
Legendary marks will be used to buy Legendary gear from vendors in The Tower, and all older marks will be converted over to Commendations. These can be switched out for reputation and the more levels earned in rep, players will be handed a Reward Package.
When you shard a Year Two Legendary item you get Legendary Marks, but Year One Legendaries will return Ascendent materials, as they do now.
Destiny: The Taken King launches on September 15 for PlayStation 3, PS4, Xbox 360 and Xbox One.