Determining Who Dropped What Item?
 

Anyone know of a way to do this?

local function OnReceiveLoot(eventID, receivedBy, item, quantity, itemSound, lootType, self)
EVENT_MANAGER:RegisterForEvent(addonName,EVENT_LOOT_RECEIVED,OnReceiveLoot)

item if memory serves is actually a link, so with the link functions becoming available soon it might be enough to get what else you need otherwise...

local function OnSlotUpdate(eventID,bagID,slotID,isNew, itemSoundCategory, updateReason)
EVENT_MANAGER:RegisterForEvent(addonName,EVENT_INVENTORY_SINGLE_SLOT_UPDATE,OnSlotUpdate)

These two combined together will enable you to track basic info on what other people receive ( although I am sure that someone was getting OnSlotUpdate to report someone nearby's update, but I haven't seen this myself ), and more specific information on what the player receives.

At current state it is not possible. Afaik in the next patch it can't be done either.

Problem is with multiloot mainly and the item looted not mentioning what it is looted from.

note to self, read question a bit more carefully ... read it as who received what dropped item not what dropped an item. My apologies.