Voting on Stack Exchange sites does a number of things. It rewards the content that we like to see when we upvote. It also signals trust, the more someone is upvoted, the more powers on the stackexchange site they get.
If we want this site to be successful, those of us that use it on a regular basis need to be upvoting the content we really like and downvoting what we dislike. This gets newer users more involved, and helps spread the responsibility of keeping the site up and running.
So please, remember to vote. It does a site good.
Note: Stolen words from Movies & TV Meta.