Giving money on charity websites is 7% more difficult than spending money on ecommerce sites. Donating physical items is even harder. For non-profit websites, social media is secondary; the top priority is to write clearer content.
User research finds significant deficiencies in non-profit organizations' website content, which often fails to provide the info people need to make donation decisions.
Although the gains don't fall into traditional profit columns, there are clear arguments for improving usability of non-commercial websites and intranets. In one example, a state agency could get an ROI of 22,000% by fixing a basic usability problem.