* Continue to provide actual new content for players, for free.
* Start selling hats
* Stop charging for the game (nearly four years later).
I wouldn't necessarily mark up TF2 as a freemium success as it only went to the model fairly late in it's life (after it had already more than made back it's budget, likely).
* Charge for your game
* Build up a loyal fanbase
* Continue to provide actual new content for players, for free.
* Start selling hats
* Stop charging for the game (nearly four years later).
I wouldn't necessarily mark up TF2 as a freemium success as it only went to the model fairly late in it's life (after it had already more than made back it's budget, likely).