My opponent plays a Torturer. I have a Trader in hand. I choose to gain a Curse and then reveal the Trader and gain a Silver instead. Does the Silver go to my hand like the Curse would have?
The Silver Gained from Trader works exactly the same as any other Gain; as Trader's text doesn't specify anything to the contrary, the Gained card goes directly to your discard pile. This situation is explicitly mentioned on page 11 of the Hinterlands instructions:
If the card you were going to gain was not going to your discard pile, the Silver still goes to your discard pile; if the card you were going to gain did not come from the Supply, the Silver still comes from the Supply.