SALSA and PageRank are algorithms that analyze the link structure of web pages to determine authoritative pages. SALSA models the web as two Markov chains, with pages as either hubs or authorities. It computes hub and authority scores to find the principal community of related pages. PageRank also models the web as a graph, and defines a page's rank based on the ranks of pages that link to it, similarly to a random surfer clicking between pages. Both leverage random walk theory to determine important pages based on the web's link structure.