Most people who used the Google Toolbar probably never went through the effort of enabling the PageRank meter, which Google offered as an incentive to web surfers, a way for them to understand the quality of pages encountered when browsing (and a way for Google to understand what people were viewing beyond Google itself). But one group was very inclined to make the effort: SEOs.
Simply put, search engine optimization (SEO) is the process of optimizing the content, technical set-up, and reach of your website so that your pages appear at the top of a search engine result for a specific set of keyword terms. Ultimately, the goal is to attract visitors to your website when they search for products, services, or information related to your business.
PageRank as a visible score has been dying a slow death since around 2010, I’d say. Pulling it from the Google Toolbar makes it official, puts the final nail in the visible PageRank score coffin. The few actually viewing it within Internet Explorer, itself a depreciated browser, aren’t many. The real impact in dropping it from the toolbar means that third parties can no longer find ways to pull those scores automatically.
Ok this is some pretty high level stuff here. There is still a lot of good information as well though. I remember when I was able to see the page rank of website on my google toolbar. I never really fully understood what it meant until later. What a person should focus on is good SEO practices to make search engines naturally want to feature your content on their search results.
Major search engines like Google, Yahoo!, and Bing primarily use content contained within the page and fallback to metadata tags of a web page to generate the content that makes up a search snippet.[9] Generally, the HTML title tag will be used as the title of the snippet while the most relevant or useful contents of the web page (description tag or page copy) will be used for the description.
Imagine that you've created the definitive Web site on a subject -- we'll use skydiving as an example. Your site is so new that it's not even listed on any SERPs yet, so your first step is to submit your site to search engines like Google and Yahoo. The Web pages on your skydiving site include useful information, exciting photographs and helpful links guiding visitors to other resources. Even with the best information about skydiving on the Web, your site may not crack the top page of results on major search engines. When people search for the term "skydiving," they could end up going to inferior Web sites because yours isn't in the top results.

If you think about it, how can a spider know the filename of the page that it gets back when requesting ? It can’t. The filename could be index.html, index.htm, index.php, default.html, etc. The spider doesn’t know. If you link to index.html within the site, the spider could compare the 2 pages but that seems unlikely. So they are 2 urls and each receives PageRank from inbound links. Standardizing the home page’s url ensures that the Pagerank it is due isn’t shared with ghost urls.
Some search engines have also reached out to the SEO industry, and are frequent sponsors and guests at SEO conferences, webchats, and seminars. Major search engines provide information and guidelines to help with website optimization.[18][19] Google has a Sitemaps program to help webmasters learn if Google is having any problems indexing their website and also provides data on Google traffic to the website.[20] Bing Webmaster Tools provides a way for webmasters to submit a sitemap and web feeds, allows users to determine the "crawl rate", and track the web pages index status.