I'll use the core set The Titan's Bastard as an example. one of his two responses allows you to put him back into your hand. Does that count if he's in the dead pile? also do responses automatically happen or can the controlling player choose not to execute them?

Responses need to be activated by the controlling player, it's not mandatory.

As for the second part, the ability only returns from play to hand. An effect must explicitly mention returning from dead or discard pile for the player to be able to do that (like Knight of Summerhall and Royal Entourage).

First part of your question, you cannot trigger his ability while in the dead card. Cards that are not in play (dead/discard pile) generally cannot trigger their effects unless the card specifically says so.

Second, Responses are what's referred to as triggered effects. Triggered effects follow the format of "Bold text:" such as "Any Phase:" "Challenges:" or "Response:" These effects are optional and must be triggered by the card's controller in order to go off. Passives on the other hand (effects that do NOT follow "Bold text:") must resolve. While the card's controller is ultimately responsible for the effect, both players should ensure that all passives do resolve.

Edit: beaten to it by Flint

AHH! This helps me a great deal!

Hoya's explanation of the difference between triggered and passive effects is spot on.

Just don't forget to apply the first part of his answer to passive effects as well as triggered effects. The "effects on cards that are not in play generally cannot be used - unless they specifically say they can be used from the dead/discard pile, etc." rule is true for passive effects as well as triggered effects.

(You probably figured that out, but sometimes, it's just good to say things like this outright.)

HoyaLawya said:

So true.