About the exclusive idea from CaptainD - perhaps some developers want to do timed exclusives.
Small ideas:
- make your game on Steam more expensive (because of the 30% of the sale going to steam)
- offer services on itch.io you do not offer anywhere else (updates first on itch.io? Support only on itch.io forums)
- know anyone working in a triple-A-studio? Let them try itch.io to bring in more customers (popularity).
A thought: steam, for example, is big. A downside of being big/very popular, is that it also brings negative things, like scammers, fake reviews and whatever you can think of you do not want in a community. (it takes time/money to combat this)