My short lecture at the Game Developers Conference 2014 Free to Play Design & Business Summit on 18 March.
Abstract: To ensure that a game stays balanced and in-game purchases remain compelling over time, it's important to design effective sinks, or mechanisms that remove items and currency from the economy. Drawing on examples from classic online games and recent mobile titles, the lecture covers eight currency sinks and eleven item sinks, including frequently used workhorses and lesser-known alternatives. Each sink is briefly analyzed for pros and cons using elementary behavioral economics to explain why players accept some sinks more readily than others. A simple spreadsheet-based approach to simulating sink impact is also introduced, useful for guiding design and live operations.