An importance system calculates the importance of pages using a conditional Markov random walk model rather than a conventional Markov random walk model. The importance system calculates the importance of pages factoring in the importance of sites that contain those pages. The importance system may factor in the importance of sites based on the strength of the correlation of the importance of a page to the importance of a site. The strength of the correlation may be based upon the depth of the page within the site. The importance system may iteratively calculate the importance of the pages using "conditional" transition probabilities. During each iteration, the importance system may recalculate the conditional transition probabilities based on the importance of sites that are derived from the recalculated importance of pages during the iteration.