I don't think very many are solely geared towards personal use. You can use all of them for business if you know what you are doing. If I had to choice one, which I do, then it would be Instagram. I feel that this one is the most used for personal use because you just post videos and pictures. Mostly to show other people how cool you think your life is or brag about how hot you are. I would use "LoL" but i don't find it very academic to use in this post.
I feel like the best one suited for business is Facebook. It has everything that you would need to promote your business. You can post videos, pictures, and even long narratives. It also has a live chat. And that is about the extent of my knowledge when it comes to social media.
Like I stated earlier in the post, all of them can be used for both business and pleasure. It just depends on the content you decide to post. Instead of pictures of your abs, you could put pictures of your product or people using your product/service.