Speaking at GDC Europe, Teut Weidemann, design lead on Settlers Online, reckons that to succeed with a Free-To-Play game you need to aggressively target your customers' weaknesses. "We have to bring them in and keep them addicted and make them keep playing." I thought this was the sort of thing you worried about journalists overhearing.
Brandon Sheffield at Gamasutra went to town on this, where developers and industry types have started to chime in on the comments. I'm not surprised. Weidemann relates the sorry predicament of free to play games having to "think about making a fun game and monetizing it at the same time," which he describes as "a huge burden."
What follows is a list of handy hints for exploiting the weaknesses in your customer base so they'll break down and pay, somewhat loosely themed around the seven deadly sins . If you make a grindy game, you can charge the slothful to speed up their levelling process. Put PvP in your game and sell combat advantages to rake in the cash from the wrathful. Offer fancy hats and dresses to exploit your users' vanity. It gets a bit tenuous when he starts talking about the lustful and how they want everything right now, so you should sell them reduced build times for infantry. Whatever floats your boat, I suppose.
Finally, Weidemann's colleague Christopher Schmitz pipes up with this choice nugget:
"Game design is not about game design anymore - now it's about business. If you think you have the same items for this year and next year, you're wrong. You have to change everything like in the Superstore."
As one commenter said, "At least he's honest."