Because Rainbow Dash.

She's quite popular, and has a dedicated and large fanbase.

And I hate that guy :okiedokielokie:

Because people cry at the most cliché of sad clichés, and because Rainbow Dash. The "emotional" part that apparently made so many people cry was just "don't leave, daddy" and "I love you forever" and so on overused quotes.

Oh, and did I mention how terrible the writing is? I honestly couldn't stand this error here, and this error there. That's not the main reason, though. I don't usually let a few minor errors ruin the fic for me, but the plot, the characters, the clichés... really, everything in the fic – caused me to dislike it.

One of the first big-time "feels" stories. Same reason Fallout: Equestria and Cupcakes are popular: they're among the first of their kind that just hooked on for a while (and now permanently).

I'm waiting for that one guy here to rant about it

I found it to be crap :/

Please note before reading that the following is an explanation and not a justification.

Many people would not judge the story based on its objective quality but rather based on the experience of reading it. If it invokes strong emotions within them, they will likely feel strong emotions toward it. When we are dealing in terms of emotional attachment, "objective quality" becomes completely irrelevant.

All of its criticisms based objective quality ("bad writing," "sad cliches," overused quotes," "cheesy," et cetera) have absolutely nothing to do with the reason people like it. Different stimuli naturally invoke very different emotions within different people. You cannot state that "sad" parts were not actually "sad," because someone might be able to relate to the sad part or it might remind them of a personal concept or experience of which you are unaware. Go ahead and criticize its objective quality, but if you are looking for the reason that people like it, that has no relevance.

In short, people like this fic because of its ability to invoke emotions, which is wholly subjective and thus unaffected by objective criticism.

Yeah I saw it, and I critized it in a comment (I'm Andrej Janka). Done very unprofesionally, looks like their cameraman took the camera first time in his life

I didn't really care for it. It was so boring, that, combined with how poor quality the writing was, lead to me not being able to finish reading it.

Honestly, It's popular for the same reason Twilight is. It's patronizing fluff. Wish fulfillment. It presents a scenario that the lowest common denominator fantasizes about, and then does absolutely nothing with it.

It doesn't bother putting even a modicum of effort into the actual writing, because it knows that the story and characters aren't a part of the appeal. The intended audience eats it up just because of the premise (which in itself is asinine and insipid). The audience just want to feel like they're Rainbow Dash's father, and in service of this fantasy, they look past the literary vomit that is the writing.

I'm waiting for that one guy here to rant about it

Sorry! Just now found this post! XD

BECAUSE IT'S SO SAD

I showed my buddy and his girlfriend the mini movie, she was balling, and he was fighting back tears.  They both do not care about My Little Pony.  It's written and acted out well enough to get the point across, that doesn't mean it's a masterpiece, or even really good, but it got the job done it tried to accomplish.  Clearly people like it enough, it has 200,000 views.   

I listened to a dramatic reading of it and honestly, I didn't like it. 

It was boring and not sad.