This chapter examines the widespread occurrence of power laws across various domains such as the Internet, biology, physics, and human society. It highlights how social network studies have extensively focused on power laws, noting their presence in areas like Weibo’s network, word usage, paper citations, wealth distribution, and product sales. The long tail theory in the Internet industry is also closely related to power laws. This chapter will cover the definition, historical development, current research status, and paradigms of power laws, as well as their practical applications and their significance in Internet contexts. Additionally, it will explore the mechanisms behind power laws using tools such as igraph and NetLogo.