This article, ladies and gentlemen, hopes to address the difference between just good synergy, and a combo. This article asks one simple question: When does synergy become combo?
To answer that, in the author's opinion, let's refer first to MTG Salvation's wiki page for what a combo is, or at least how it's defined there;..
http://wiki.mtgsalvation.com/article/SlangComboShort for 'combination', combo can refer to a variety of concepts.
- Card combination: Any combination of 2 or more cards which produces a beneficial effect, designed to gain an advantage over the opponent.
- Combo deck: A deck or archetype which uses a combo as its victory condition. The deck is designed entirely for the purpose of setting up and protecting the combo.
SynergySynergy refers to the small, positive interactions of individual cards in a deck. A synergistic deck is one where every card benefits from every other card in some way or fashion. Even a deck full of seemingly bad cards can be a good deck if it showcases potent synergy. Tribal decks, such as Goblin or Elf decks, rely on synergy to win games.