Originally Posted by
Lora Craft69
(Source)
You see the bar under your name and rank, that's the reputation bar.
The more reputation you get the longer this bar becomes until it's full.
I give rep when I like something, funny post, clever post, great screenshots or videos, etc.
Many times we also use rep to attract a persons attention to a reply post you just made.
I sometimes also give rep to let a person know I appreciate his post, for example when they thank me.
So in that regard it could mean a lot of things.