Basically, ReddCoin is used for tipping friends, family or people on social media. It changes the typical like button on Facebook (you are rewarding people for their posts with actual coins/money). You can tip on Facebook, Twitter, Instagram, Youtube, basically, any social media platform.
I think they planned to enable tipping on all those platforms, back in 2014, but never got round to developing anything. They had a tipbot on reddit, but then went away and set up their own forum because they kept getting trolled on reddit. Which doesn't sound like a very social coin at all!