Destiny: you won't be able to trade your loot with other players on launch
Being an MMO, a huge part of Destiny's gameplay would naturally involve finding loot, comparing it with others, and maybe trading it as well. Except Destiny won't allow you to do the trading part, at least not at launch.
Answering a fan question regarding trading following the weekly update, Bungie replied, "As for swapping irons in the Tower? Nope. We want you to earn ‘em. You should be able to tell a badass story for every sweet jewel in your arsenal."
Later confirming that you can however trade items between Guardians [characters] under your account.
Gamespot adds that Bungie had noted before that it will consider adding the feature down the road if the community wants it.