@Chaotic Note
 
it doesn’t rhyme with bloom.
 
unfortunately that blog post has malicious javascript adverts, so nobody should read it or they might end up giving money to asshats.  
but I’m sure there’s some great wisdom beyond that “and click here for your free free trial of __” thing.
 
the blog can’t be right though, because “her” is also the possessive form, so it’s a lot more confusing than who/whom.  
only “I/me” has the same relationship as who/whom, so it’s not completely incomprehensible to use whom, just caveman speak.
 
“me was obsessed with this magical bloom”
 
…unless you’re scottish. then “me” is also both objective and possessive, there’s no parallel to who/whom, and nobody can understand what you say anyway.

@redweasel  
Actually I do believe ‘who’ works. Why? In accordance to this blog post about grammar, let’s try substituting ‘she’ for ‘who’ and ‘her’ for ‘whom.’
 
She was obsessed with this Magical Magenta Bloom.
 
Her was obsessed with this Magical Magenta Bloom.

>not using whom
 
>not using whom
 
>>801742t (deleted)

Those aliments must be pretty bad for Twilight to hype this up.

Well, let me say that according to Treehouse, A Health of Information comes after Daring Done, but they had to shuffle up the episodes so the comics will catch up.

@Background Pony #21DC  
Given the way all of Zecora’s lines are given in this, the letterer is bolding the rhyming ones. It’s definitely “who”/“bloom”

@Marvelous TK  
I think it was brook with bloom

did - did this just rhyme ‘who’ with ‘bloom’

@Twitter-Mites  
I mistagged, it’s the next ep, Health of Info

How does this tie in with It Isn’t the Mane Thing About You?