I through the ball? I threw the ball.

     The difference between through and threw. First off, they aren't even the same parts of speech. Threw is a verb, meaning it represents an action. Through is a preposition, meaning it indicates the spacial position of something. Therefore it would make no sense to use a preposition as a verb, which people SO often do.
     This is what I always see:
I was walking threw the yard.
      and
I through the ball to my dad.

     See the errors? In the first sentence, since it's not telling an action, the preposition should be used.
In the second sentence, it is supposed to be telling the action of throwing the ball to dad. Instead, it uses the preposition which is incorrect.

     I was on Twitter today and saw this mistake TWICE on my news feed. Twice. Then I really felt the need to rant and straighten this out because it's not just some "typo," people really have no idea the difference between the two.