The ItemID of the item that is to be added to the watch list. The item must be a currently active item, and the total number of items in the watchlist (after the items in the request have been added) cannot exceed the maximum allowed number of watch list items. One or more ItemIDs can be specified, each in its own ItemID container. A separate error node will be returned for each item that fails.
See the
Field Index to learn which calls use ItemID.
