Used by imbeciles to describe an abundance of something. When in fact there is very little of that something.
You and 3 of your friends are on a camping trip You: "Wow, I sure am hungry this morning"
Friend #1: <grinning ear to ear> "Don't worry bro, I made a shit-ton of pancakes for us!!"
<The pancakes are pulled out, and there are 6 of them. That's right, 6..... for 4 adult males.>
You, Friend #2,#3, and #4: <stare at Friend #1 in utter disbelief and disappointment>
An actual unit of measurement. Just below an ass-load and right above a fuck-load. Consider two million views for a YouTube video in two days as an example.
"...but this video did get just under two million views in about two days-which is what scientists and scholars refer to as a shit-ton of views."
-Ray William Johnson from the =3 episode "WANNA FIGHT?"