1. Facebook is that person who is really into politics, appears very religious, may be into conspiracy theories, and wants you to think they have the perfect life.
2. Instagram is the hipster who is cooler than you, and might be a good photographer.
3. Twitter is always up on the latest info, pretty honest, and doesn't go on long rants.
4. LinkedIn is the perfect employee, who read all the management books, and has lots of letters after their name.