Age of Empires Online. But hey, don't blame Massively! It's actually the title of a speech given by Microsoft's Kevin Perry at GDC Europe 2013. Gamasutra has posted video of the event, and it's well worth watching if you've got 45 minutes to kill and you're interested in what goes through a developer's mind as he thinks about continually evolving monetization schemes.
Perry says that this particular speech is on its third iteration. It initially started out positive when he shared it with an internal Microsoft audience some time ago. He then reworked it based on newly collected data about the game for GDC San Francisco earlier this year. And then he reworked it again for GDC Europe based on even more data. If you're sensing a trend here, you're right: game devs often don't know how well their business models are performing at any given time.
As Perry says, "it's an ongoing conversation."
There are a few other choice quotes as well, including the notion that PvP players are small in number but "very, very loud" in terms of influence as well as the supposition that you can launch incomplete games under the F2P business model and "sort it out on the fly." This last bit isn't always true, Perry says, "especially for a large, branded title."