PageRank is basically algorithm systems in order to calculate the 'importance' or 'popularity' of a page with a particular topic searched on google. It begins with rank 1 (the highest rank and also it is the first page/link we can see when we search something on google) to 10, and then continue on. As for most of the time people will just click on what they see in the first google search page, if the link we are working on is in the first page then more and more people can access to our business.