These are two things that I see confused a lot. It's not really a big deal (especially since these cards are designed purely for our own amusement), but I just thought some people would like to know the difference.
A triggered ability, you all know and love.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
This is Sword of Feast and Famine's triggered ability. It also has a static ability and an activated ability, but we can tell THIS one is triggered because of the "whenever". "When" and "at" are also good ones to look out for. It's effects are put on the stack after its trigger conditions are met.
If Blighsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.
This is a replacement effect. This doesn't happen once its condition happens, this happens INSTEAD of its condition. In this situation, the Blightsteel Colossus would never be put into a graveyard at all, because it's shuffled into your library instead. Note the "If" and the "instead" so you know it's a replacement effect.
A lot of designers on this forum sometimes word replacement effects like this:
WheneverBlighsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.
The game can't see into the future. It can see what's immediately just happened, but it doesn't know what's about to happen. Even if the ability triggered of it entering the graveyard, it would then be trying to replace something that had already happened, and this is NOT a case where the game 'rewinds'.
In short, triggered abilities look for what JUST happened, replacement effects look at what's happening now.
Hope you found this interesting, and lets see some cool replacement effects!
Private Mod Note
Rollback Post to RevisionRollBack
Modern GWU Next Level Blue
Legacy UW Mono-U Control
Commander BGW Ghave
(developing) UBG The Mimeoplasm WUBRG Horde of Notions
I appreciate posts like this tremendously. Although I try to keep my wordings clear, sometimes I will goof up or not remember how I intend for a card to function. I think a series of posts like this about common mistakes would go a long way towards keeping this forum polished. With enough posts, a Table of Contents for "Card Design Conventions" could easily get stickied.