Earlier quoted context omitted.
I've had a chat with someone who used to work for Zynga, and he said it was a great place to work. He said they knew full well the psychology of what they were doing, and were quite proud of how well they do.
I wonder if they hired psychologists for this?
Super Mario Bros.
Think of the "levels" of achievement:
1) On the smallest level, you kill small enemies, get a "big" mushroom. You get points, and your environment changes.
2) On the next level, you collect coins. 100 means an extra life.
3) Then you beat the sub-levels, 1-1, 1-2, 1-3
4) Finally you beat a "boss" and go to the next "World" to 2-1, 2-1
5) Beat 8 "Worlds" and the "big boss" and you beat the game.
6) Advanced players will compete for the best times, try to create fireworks over the castles, find warp zones, or max out their points.
The key is in progressive achievements and always wanting more. You create a sense of urgency or need and you have someone in the palm of your hand.
Business is no different. I just upgraded my Basecamp account so I could add the "Time" module. I'm on World 2 now.