Most Helpful Girl
Pinterest. I don't have snapchat because I think it's stupid. I got rid of my Twitter because I got bored. I only use Instagram for its filters, and have been debating getting rid of my Facebook for a while. Pinterest is the only one I like and use regularly.
Most Helpful Guy
Facebook because it has more of a focus on communicating with other people (compared to their competitors, imo) than it does on spreading global news, swapping selfies, or showcasing photography.