What is a Pagerank?

As per Wikipedia, PageRank is a link analysis algorithm that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of "measuring" its relative importance within the set. PageRank was developed at Stanford University by Larry Page (hence the name Page-Rank) and later Sergey Brin as part of a research project about a new kind of search engine.

Alexa Page Rank Check
Google Pagerank Check
Compete Page Rank Check
Quantcast Page Rank Check