Search engine optimization metrics

A number of metrics are available to marketers interested in search engine optimization. Search engines and software creating such metrics all use their own crawled data to derive at a numeric conclusion on a website's organic search potential. Since these metrics can be manipulated, they can never be completely reliable for accurate and truthful results.

Google PageRank

Google PageRank (Google PR) is one of the methods Google uses to determine a page's relevance or importance. Important pages receive a higher PageRank and are more likely to appear at the top of the search results. Google PageRank (PR) is a measure from 0 - 10. Google PageRank is based on backlinks. PageRank works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites. However, Google claims there will be no more PageRank updates, rendering this metric as outdated. As of 15 April 2016, Google has officially removed the PR score from their Toolbar.

Algorithm Overview

1Link Analysis

PageRank evaluates the importance of a webpage by analyzing its inbound and outbound links. The algorithm assumes that a page is more valuable if it is linked to by other important pages.

2. Importance of Links

Not all links are equal in PageRank. The algorithm assigns a numerical weight to each page based on the number and quality of links it receives. Links from pages with higher PageRank contribute more to the target page's importance.

3. Damping Factor

PageRank introduces a damping factor to account for the probability that a user will continue clicking links rather than stopping. This factor helps prevent infinite loops and ensures a more realistic representation of web navigation.

Mathematical Formulation

The original PageRank algorithm is based on a mathematical formula that calculates the PageRank score for each webpage. The formula involves iterative calculations, and the algorithm converges to a stable set of values representing the importance of each page.

Impact on Search Rankings

PageRank was a breakthrough in search engine technology, significantly improving the relevance and quality of search results. Google used PageRank as a key factor in determining the order of search results, with more important pages appearing higher in the rankings.

Evolving Landscape

Over time, Google has evolved its search algorithms, incorporating various factors beyond PageRank. Today, while PageRank still plays a role, Google uses a complex set of algorithms that consider hundreds of signals to deliver the most relevant search results.

Criticisms and Controversies

Despite its success, PageRank has faced criticism, including concerns about potential manipulation and biases. The algorithm's reliance on links led to the rise of practices like link farms and link buying, prompting Google to refine its algorithms to combat such issues.

Legacy

PageRank remains a historic milestone in the development of search engines and web navigation. While its direct influence on search rankings has diminished, its principles continue to inspire and shape modern search algorithms.

Alexa Traffic Rank

Alexa Traffic Rank is based on the amount of traffic recorded from users that have the Alexa toolbar installed over a period of three months. A site's ranking is based on a combined measure of Unique Visitors and Pageviews. Unique Visitors are determined by the number of unique Alexa users who visit a site on a given day. Pageviews are the total number of Alexa user URL requests for a site. Alexa's Traffic Ranks are for domains only and do not give separate rankings for subpages within a domain or subdomains. At the end of 2021, Amazon announced that the Alexa project was going to be discontinued on May 1, 2022.

Moz Domain Authority

Domain Authority (DA), a website metric developed by Moz, is a predictive metric to determine a website's traffic and organic search engine rankings. Domain Authority is based on different link metrics, such as number of linking root domains, number of total backlinks, and the distance of backlinks from the home page of websites.

Netcraft

Similar to many other websites like Alexa, Netcraft features a toolbar that provides users with the ability to view page-hit popularity and various web server metrics along with aggregated user provided website feedback.