This belongs in Forum Feedback, so I'm moving it there.
The Winpoint system is a way of showing an opinion of someone's post. Winpoints, being that someone likes your post for its content, for it contributing something worthwhile, or for a post being a popular opinion among the Slender Nation users.
Negative Win Points, or Failpoints, are when someone does the opposite. Such as; make a post of no relevance to the forum or specified sub-forum, an in-character post, an unintelligent and/or disrespectful post, or make a post that people consider as something that's not accepted by the general Slender Nation public.
Hope this helps.