If you think Facebook and YouTube are your most preferred social media platform then you may be wrong. No doubt that they are most popular, but do they solve your purpose. Just because a site is popular doesn't mean it is a good fit for you business and online services what you are offering.
To guide you decide which social media platforms is best suited for your business, here is a nice infographic created by QuickSprout, that explains which social sites you should be leveraging based on real data and according to the social media strategy.
Source: Quick Sprout