I believe that for a game to be successful, it is best to figure out how the users will be able to participate in a community of users, and how they will be able to brag about their experience.
This became really obvious to me around the time the latest “Zelda” was release on the N64. That game has a set of rewards really well distributed along the linear path of the game. Each one of those rewards is in fact a piece of vocabulary that enables users to brag about their experience and how far they have been in the game. Clearly the ultimate success in Zelda is to finish the game, but before you get there you have plenty of opportunities to brag to your friends about how far you are: child or adults, whether you got the horse or not, whether you got the sword etc… In a conversation with a player, with just a few questions, you can know exactly how far they are in the game. This is a very powerful mean of self promotion of the game, and it is clearly developing something that will make the game forever memorable to the user.
This is so much more powerful that just providing a score, that we even when a score is the “obvious” measure for the game, we should reward the user with more than that.
For Maxis, I am focused on providing better publishing tools for the web. After the launch of SimCity 3000, users were creating more web sites about SimCity than they were sharing cities. Yet SimCity is a tool to create cities, not web sites. Maxis is changing that now and making every game a great publishing tool to make web sites. This is how we will satisfy mainly the “Brag” factor.