Chaining

Let's say you're dueling. Your opponent activates the Spell "Tribute to the Doomed." Your Tutan Mask can negate "Tribute to the Doomed," before it destroys your important "Red-Eyes Zombie Dragon." This is a chain. A chain occurs when a card effect is activated that negates and/or destroys other cards. However, Chain Links work in Spell Speed. A monster effect and a Spell Card effect (excluding Quick-plays)are effects with a Spell Speed of 1, the lowest Spell Speed. A Quick-play Spell and a Trap Card (excluding Counter Traps) are cards with a Spell Speed of 2. Counter Traps are the only cards with a Spell Speed of 3. A card can only counter another card if it's Spell Speed is equal to or higher than the card it is trying to counter. This is an example of an acceptable Chain Link:

You use "Tribute to the Doomed" (Spell Speed 1) Your opponent counters with "Tutan Mask" (Spell Speed 3) You counter with "Seven Tools of the Bandit" (Spell Speed 3)

Now, this Chain could go on and on for quite some time, but it would have to now include only cards with a Spell Speed of 3 (Counter Traps).

You could actually go ahead and make (or try to make) a deck that revolves around Chain Links. There are cards out there that support Chain Links. Here are a few of them:

MONSTERS:

Man Beast of Ares Blast Asmodian

SPELLS:

Chain Strike Chain Summoning

TRAPS: NO TRAPS FOUND YET