Pinkie pie is implied to be Bisexual. but it's stated in some episodes.

You Can Briefly see blood on the "Smile HD" clip on the intro

Diego Leiva Described he would Portray Fluttershy as "Eerily Agressive"

One of the drafts says Twilight and Pinkie pie will chew each other's hoofs out.

(YouTube)

(Vimeo)

Words like "hell" "damn" and "bastard" are very common.

The PG episodes don't go further than "ass" but an Episode Rated 14 can have uncensored uses of "shit" "bitch" "dick" "asshole" etc.

"fuck" "cock" and "cunt" are all censored on YouTube. but not in Vimeo.

"Cupcake Complex" is about a hallucinogenic cupcake.

Themes like drugs, cannibalism and genocide are used for comedy.

Some images can be shocking, triggering or seizure inducing.

The show takes blatant inspiration from Spliced and Family Guy. So It's obviously not for everyone.

In Terms of Content. This is Below Family Guy. But above the Simpsons