I had this thought a few days ago. Charitable donations would be a great way to combat the FUD (fear, uncertainty, doubt) from competing crpytocurrencies and other people who don’t understand where the money comes from.
Secondly, enabling the smart contracts that @Dan mentions could enable us to not just split earnings between different users, but between different charities too.
I agree - let's establish ourselves as a positive and progressive community by giving away some of the $ created to charity.
The ability to tip directly to the charity page, or from the outset split your post earnings with a charity of your choice.
For sure this could also draw big companies to build a presence on Steemit because they are seen to be donating to charity rather than caring about their own profits.
A possible cap on absolute earnings might be an option too - it would reward the community and remove the temptation to sign up and immediately cash out.