It's mostly for show. You can't buy anything with it, and you can't elect to use it for visibility (though reputation, which it's a proxy for, can achieve this

It's mostly for show. You can't buy anything with it, and you can't elect to use it for visibility (though reputation, which it's a proxy for, can achieve this effect). Others can see it on your user page if they click through from a comment you made. You gain karma when a comment or submission is voted up, and lose it when it's voted down. Voted down? When you cross a certain threshold (500?), you're trusted with the ability to down moderate comments that don't contribute: http://ycombinator.com/newsguidelines.html http://ycombinator.com/newsguidelines.html