Karma is all about gamification. Made up points to make you feel like your contribution was worth something. You can see it in pretty much all social media platforms.
You never really care about checking others, but I bet you'd probably take a peak from time to time at your own.
I never cared, but I would be lieing if when I post blew up I wouldn't notice all those upvotes.
fftaco
Mostly_Harmless
paorzz
bellizziebub