Who vs. Whom!

I was watching "the office" and it was the episode where they argue about whether or not to use who or whom? I realized i did not know the answer, nor did there explanation suffice, so I looked it up.
Who is the subject. ( who do you think you are?)
Whom is the direct object. ( whom do you think you see?)
Who will follow after the pattern of he and they.
Whom will follow him and them.
It almost seems like to much work to decide how you want to form the sentence when you are saying it, but when you are trying to sound more academic then it will become important.

http://englishplus.com/grammar/00000021.htm