Gamasutra's Simon Carless recently published a blog post highlighting the importance of measuring the number of people who have wishlisted your game on Steam as an indicator of how sales will pan out.
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But I have good news for you. There’s already a way to work out if your premium, non-F2P game launching on Steam* is going to be a success or not. And I really feel like many people don’t understand this.
The entire post can be viewed here.