[ManakaJunpei]

In my opinion you should gain NPS also when you either receive positive reputation or somebody adds a "thank you" on your post.

They are both behaviours that in some sense certificates that somebody has remain satisfied of your actions (thus are valuable for the community.). 

Speaking of NPS, this acronyms stands for?

Just my humble opinion.

I assume u mean "NSP" not "NPS" either way I'm interested as to what it stands for too.