PageRank is a numerical value that denotes the importance of a page on the web. It is a concept that is extensively used by Google. This ranking to a great extent determines the positioning of your webpage in the all-important Search Engine Results Page (SERP). Thus, a PageRank determines your online visibility and hence, can be termed the lifeline for your webpage or even your online business presence.  The concept of PageRank was invented by Larry Page, a co-founder of Google in the late 1990’s. Unlike traditional search engines, Google uses two key parameters to measure the importance of a webpage and position it suitably in the search engine results pages

1. Relevance
2. Importance

Relevance is decided upon by the text in the webpage – by determining if the content is relevant to the words typed on the search box.Importance, on the other hand, is determined by how many pages are linked to a particular webpage. It is assumed that all visitors to a particular web page are human. It is also assumed that visitors add links to pages that they find are relevant, important and useful to them. So, when a page has several links, Google assumes that it has a high degree of importance in relation to a particular search query. So, people, indirectly, decide the PageRank of a particular webpage.   Initially, Google assigns a numerical value to every webpage that it encounters and this value automatically increases as the numbers of links to that page increases. This PageRank eventually determines the relative importance of a webpage vis-à-vis other pages that are equally relevant to the search query. 

 Some people confuse the real PageRank as calculated by Google with the Toolbar PageRank that is now an add-on feature in most web browsers. A Toolbar PageRank is assigned a numerical value anywhere between 0 and 10 and can be seen on the web browser. Google categorizes all the relevant webpages for a particular search query logarithmically in any of these eleven ranges. So, the Toolbar PageRank is not the same as the Real PageRank that Google uses to rank its pages in the search engine results page. Furthermore, the Toolbar PageRank is updated only once in 3-4 months and is not an accurate indicator of the webpage’s current ranking. The Toolbar PageRank can be used as a very lenient point of reference but is not indicative of the real PageRank.