Last night, I had a dinner meeting with some entrepreneurs and we were talking about how to make users stick to a website from a community standpoint. These points were:
1. Socializing - satisfying the need for humans to connect with other humans is great attractor for people to stick around. They communicate, meet, make friends, etc.
2. Sex - once you get Socializing, then the next natural extension of that is wanting to meet for dating reasons or sex.
3. Competition - somehow, enabling people to compete against one another and make them feel better than others by winning contests, acquiring more goods or power, is something that people like. There is the prestige factor of feeling and being better than others.
4. Fame - along with competition, if you can increase one's opportunity for fame when they win, then there is a natural desire to keep competing and retaining that fame and being on top. It's all about bragging rights to your friends and strangers....
5. Fortune - this was one we didn't discuss, but I just thought of. Allowing people to make money out of their activity, or acquire real or virtual wealth, helps keep people on the site. Reward for activity and participation only makes people want to participate more. As in the real world, the pursuit of wealth is on many peoples' minds.