I mean i just got back to plurk so i feel so noob to ask but what is the 'star' thing ?

this one...

i dont see that option, must be if you have plurk coin

catte : ooo i see its about plurk coin option x-x well still dont know what its doing

It allows you to bookmark a particular plurk.

Rune🐻ofAgamotto : Oh! omg thank youuu

it's like "liking", but for the bourgeois class

/usr/sbin/ennui : ooo i learn new thing ! thank you