PageRank is a common way to measure the importance of various website pages. PageRank works by counting both the quality and the number of links to a page in order to calculate an approximation of the level of importance of the website. This works by assuming that websites which are considered important are likely to have more links from other websites.
It is the first algorithm that Google used to order their search engine results. It operates as a link analysis algorithm and it assigns a number weight to each element of a set of documents which are hyperlinked. The pagerank algorithm can be used on any collection of entries that have reciprocal quotations and references.