This subject has been on my mind for a while now. I suppose it is a bit presumptuous of me to try to define the laws of the Internet. On the other hand, why not me? :) Anyway, there seems to be one truth about the Net in my 20 years of participation.
The First Immutable Law of the Internet: If a system can be gamed, it will be gamed.
Whether it is a "like" system on a social network, a link ranking system, or a simple voting application, if the results can be manipulated, they will be.
Too often systems are designed with the naive assumption that users will act on the honor system. In my opinion, the vast majority of users do. However, there will always be enough smart people that don't follow "the rules" of a system. Eventually, someone or some group, will end up owning the top rating, the highest page rank, or most liked story by not following the rules. World of Warcraft saw this happen with their PVP rating system. Google constantly battles it with its page rank system.
So when you are out there, developing the next great thing, remember the first law. Assume someone will attempt to game your app. Because if you don't, inevitably someone will do just that. :)