Why are they so popular? What are success stories (aka case studies) used for?
We're going to answer the second part of that first and then tell you why they're so popular.
What are success stories (aka case studies) used for?
Companies use success stories in a number of ways: (1) sales training and internal training for new employees, (2) webinars, (3) great fodder for newsletters, both internal & external. Those are the top 3 uses, although I'm sure you could think of more uses for success stories.
Why are they so popular?
Ahhhhh, now there's the crux of it. They are quite popular in the b2b world and there's a good reason for it. They speak to our most ancient instincts (reptilian brain aka the amygdala) about storytelling. Not only are they telling us a story, but it is the most ancient story of all time: The Hero's Journey.
The Hero's Journey is a mythic story that is told over and over and over again. It's one of the major themes used in blockbuster films (think Star Wars, Independence Day, and the Lord of the Rings trilogy). It's an archetype story that speaks to all people across the globe regardless of culture, language, or any other "differences." It's a story about growing up, about facing obstacles, overcoming those obstacles and becoming the hero to save the galaxy, save the universe, save the world, or in our case save the company.
And you just thought they were marketing stories, didn't you? ;>