Subscriptions were supposed to be a way for you to find out when someone you liked posted new videos.
But no, now it's used as a measure of popularity.
my friends all call me weird because i've liked ~100 videos, favorited 150+, and subscribed to at least 200.
every video i liked was because i really seriously liked it, anything i favorited was because it was cool to show to other people, and anyone i subscribed to was because i wanted to see what they would post next.
in fact it wasn't until recently that i realized subscriptions were becoming more and more like useless facebook likes.