I need clarification on this.

Sorry but what does metagame refer to?

 

metagame means when you use outside knowledge to your advantage.

example:
you know your opponent loves to play a certain style, you automatically op to counter it without scouting.

its you being prepared for a certain match because of something you know.

 

So in other words it helps to be diverse and not stick to one style.

 

thats not what I said but that is ideal way to go if you don't want someone to metagame you.

 

Ok so like if I was a brood war Zerg against Bisu I would do some sort of air attack right?

 

Kinda, althought bisu would counter it... but yes because you know he loves his zealots and reavers, going straight to air units would be metagaming. In order to not metagame, you would have to scout that he is in fact going zealots and reavers then teching to air units.