Some non-profits who are doing great things on social media are The Royal Flying Doctor Service, One, American Red Cross, and the Christopher & Dana Reeve Foundation.
Here are some great social media tactics for Non-Profits, courtesy of Blackbaud.
This Non-profits on Facebook Page is a resource for non-profits and other organizations for social good, built it to help you harness the power of Facebook and bring positive change to the world.
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