In other words:
Blissey variants being mainly weak to Fighting types, the metagame for it is anything Fighting,
Mario being weak to Psychic, the MEtagame is anything PSychic.
and so on!
Metagame is important to monitor in your local area as it gives you an idea (not necessarily and advantage) as to what might and might not work! Garchomp in the seniors here might be a bad choice since it is weak to :colorless and Blissey is :colorless. It also allows you to get a good tech card rather than a bad one!
Good Job Andy!! REMEBER SOTG AT ALL COSTS is the GREATEST VICTORY!!
^Well said. To add on to that, metagame even goes so far as to how you run your trainer line. Example: areas with little Cessation Crystal (locked powers) or Buffer Piece (damage reduction) don't call for Windstorm to counter them as often as metagames with it.
A great example of advanced "metagame" was back in 2005 when Battle Frontier (shuts off all evolved C, D, and M powers/bodies) first came out. Since the entire format revolved around Pidgeot, Battle Frontier was a VICIOUS card. Its impact was so huge that people, for the first time in years, actually played 3-4 stadiums per deck.
Metagame is so influential in this card game that it determines:
-What deck you use, period (as Mr. Fish pointed out!)
-What basics and/or stage 1's of a line you run.
-What kinds of draw cards you run.
-What energy you use
...and so on. In other words, metagame owns us all! It's always a critical thing to consider during the deckbuilding process.
So with that in mind, all you really have to consider right now (at least until the next set) are Blissey variants and Team Galactic's Wager (with the occasional cessation crystal lock). If you can beat a solid Blissey list, and if you can consistently recover from losing a Wager, then you have an excellent deck that can be competitive with anyone.