Encouraging user-generated content

1. Gameplay Achievements vs Social Achievements (Gamification Achievement Systems Tips)
2. Game Teaser vs Game Trailer (Player-Centric Gamification Tips)
3. Player Market vs Game Market (Virtual Economy Gamification Tips)
4. Rewards vs Incentives (Player-Centric Gamification Tips)
5. Single-Player Achievements vs Multiplayer Achievements (Gamification Achievement Systems Tips)
6. Tradable vs Sellable (Virtual Economy Gamification Tips)