PageRank is a method for ranking web pages based on the link structure of the web. It was developed by Google to help search engines make sense of the vast heterogeneity of the World Web. PageRank works by treating individual web pages as nodes and links between pages as edges, and recursively propagating importance weights through this link structure. It helps address issues like some pages having more backlinks due to their popularity rather than their actual importance. The algorithm involves iteratively computing the PageRank scores until they converge based on the link structure and a damping factor.