Each one of the big jumps and drops have a story behind them. A game might have received better in store play support (Pokemon), the company may have had some big hits (Z-Man), or in the case of Wood Expressions, they changed their packaging to be more retail friendly and we jumped on board.
Edit: What I see from this is the top games hold steady, moving around a bit, while a bunch of newcomers have entered the second tier, pushing weaker established games downward. One caveat: Since this is only three months of data, it's more susceptible to small shifts, such as new releases for each game.
Magic: The Gathering | +1 | |
Warhammer 40K | -1 | |
Warhammer Fantasy | +2 | |
Dungeons & Dragons | -1 | |
Fantasy Flight Games | +2 | |
Rio Grande | 0 | |
Flames of War | +4 | |
Mayfair Board Games | 0 | |
Pokemon | +55 | |
Hordes | +19 | |
Yu-Gi-Oh | +5 | |
Wood Expressions (classic games) | +41 | |
Z-Man Games | +18 | |
Warmachine | -7 | |
Days of Wonder | 0 | |
Dark Heresy | -7 | |
Star Wars CMG | -5 | |
Naruto | -4 | |
World of Warcraft CCG | -6 |