Combine the strategic planning and placement of tower defense with the leveling, skills, and fast-paced combat of defense of the ancients, and you've got Dungeon Defenders, coming this fall to Xbox Live Arcade, the PlayStation Network, and PC.

That's the impression I'm getting from these graphs, showing how many titles were offered for sale/download on each of the platform holder's online services since launch. While the numbers obviously fluctuate from month-to-month on all three - Xbox Live, the PlayStation Store and the Wii Shop Channel - general trends…