Sometimes when an app seems simple, math proven in a seemingly unrelated field may be involved. In this case it’s a variant of the Laplacian operator being used to analyze social networks. You don’t need to know this math to use social networks, but if you want to get the most out of them or better yet realize your own vision of one you need to at least know people who speak the math. Often that’s a physicist or engineer and getting to know them socially can be a good way to tap into what they know. OTOH, if you are deeply literate in math and want to help the villiage, or start a company or find a different work environment sharing this kind of information can help.