4.1. Literature Review
Through the literature review we found that the factors as shown on Table 1
impact the ranking of websites in search engine indexes. On Table 2
the matching of previous researches to indexes is presented.
The most mentioned factors in the above papers include the quality and quantity of backlinks, the social media support, the keyword in title tag, the URL length, and the website structure.
Page size and website loading time: A very important on-page factor for the optimization of a website is the loading time. Search engines include this factor in their algorithms too. The higher the loading time, the lower the ranking of a website in the search results. Although special effects and graphic elements upgrade the image of a website, the excessive use of them may increase the loading time of the website. Loading speed is affected not only by graphic elements but the HTML file and all the elements regardless of their file type contribute to the size of a website and affect the loading speed. Most search engines will not fully index pages that are greater than a certain sizeKeyword in title tag: The title tag refers to the title of the file. Every HTML/XHTML file contains a title element. The main use of the title tag is to determine the title in the toolbar of the browser, it shows the title of the website in the search results and the name in the ‘favorites’ tab. Concerning this factor while structuring a website it is easier for the search engines to trace and rank it in their search results.
Keyword in h1/h2/h3 tag: Equally important on page intervention is the use of keywords in h1, h2, and h3 tags. This element is the second most important on page factor for higher ranking in the search results. The websites with optimized and targeted h1, h2, and h3 tags are ranked higher by the search engines. This happens as the crawler searches for information regarding the content structure of every website and the best way to extract this piece of information is to search on these tags. Skipping this part of optimization is a big obstacle on the way to higher ranking.
Keyword density in text: The keyword density is the number of times the targeted keyword appears in the text of a website compared to the rest text. This on-page factor and the frequency of times the keyword appears in title tag are considered some of the most important factors when optimizing a website. The ideal keyword density range is 2 to 8% of the text of the page but this range is not universally true and is affected by other factors. We have to pinpoint that the keyword density should not have negative impact on the readability of the text because it is perceived as negative element of a website by the search engines
Keyword in URL: It is easier for crawlers to trace a website if its URL contains the targeted keyword. In general, search engines tend to rank higher websites with .edu and .gov domains as these domains are used by state and educational websites. However, optimization for all types of websites can be achieved if the length of the URL is kept short.
Keyword in meta description tag: The meta description tag is a summary of the content of a webpage. This tag contains the text that appears in the search results of the search engines just below the link. The meta description tag is a guide on what keywords should the website be indexed for by the search engines
Alt text: To be ensured that the most elements of a website are indexed correctly, they have to be in HTML format. However, content such as images and videos need more information to be indexed by the search engines. Webmasters must use an alt tag for images and a transcript for videos to provide enough details about those types of content.
Unique high-quality content: Search engines prefer websites with unique, authentic, and quality content. If the content of a website is plagiarized from another website it will not be ranked high by the search engines. In addition, a frequently updated content has better chance to get ranked higher in search engines for related keywords.
Title length & Description length: The title of the website must reflect the topic of the website without unnecessary information. With the use of a short and comprehensive title, website visitors can understand the main topic of the website. Google suggests no more than 70 characters for title tag. The meta tag description offers some pieces of information in the search engines about the website. A poor or no description in this tag suggests a low-quality website. On the other side, larger than standard text (up to 155 characters recommended by Google) may be considered spam as the targeted keywords may be used excessively.
URL length: The URL represents the address of the site in the World Wide Web. As mentioned above, the targeted keywords should be included in the URL, so it can be traced easily from the search engines. To become even more SEO-friendly it should be short and understandable.
Text length: Websites with longer text tend to rank higher in the search results compared to the ones that have less or no text at all. This proves that search engines prefer content rich websites. This assumption may correlate with the fact that in richer content the targeted keywords appear more frequently. Besides, users prefer longer text as it is more informative. Text to code ratio: The text-to-code ratio is a metric that represents the ratio between the text in the front-end part of the site to the back-end code. The ideal ratio range is 25 to 70%. This ratio refers in the visual text compared with all the HTML elements including the image tags and other visual elements. Although this factor is not directly correlated to the ranking of a website, there are many factors that are based on this factor, so it is crucial to be considered for a more effective SEO strategy.
Internal linking: A very important SEO factor is the linking of the individual pages of a website. The goal of internal linking is not only to make the visit of the user more enjoyable but also to facilitate the tracing and the indexing of the individual components of the website. As a result, a higher ranking of the website is achieved, given the fact that the value that is passed by the external links is shared uniformly in all subpages of the website. Finally, it should be mentioned that internal links must be checked regularly to trace any broken links.
Quality and quantity of backlinks: The quality and quantity of backlinks is one of the most important factors for optimal ranking. Backlinks are references from other websites pointing to the targeted website. Google, in order to determine the importance of each website for the user, invented an algorithm that calculates the value of the website based on the references from other websites pointing to the given site. The algorithm takes into consideration the number as well as the quality of the incoming links. This algorithm is called “Pagerank” and uses a 0 to 10 scale to determine a relative score of that page’s importance and authority. The ranking of a website heavily relies on the Pagerank algorithm, which is the only factor that has remained unchanged despite the updates made in the ranking patterns. Considering the importance of this factor, building quality backlinks that are referenced from a high number of websites is extremely important to achieve high ranking. Depending on this, webmasters started implementing black hat SEO techniques such as purchasing links, arranging for links provided by link farms, and link exchange with other websites to quickly build inbound links. As soon as these techniques became known to search engine programmers, websites using these link-building strategies were banned and the algorithms were changed in order to value quality over quantity. Therefore, when building backlinks, the authority of the linking sources and the topic relevance of the linked sites must be considered.
Website structure: Having a clear navigation system is a standard requirement for a useful website. Some websites use frames and navigation buttons made in java or other programming languages which are not traceable by search engines. The solution to this problem is the creation of a complementary navigation bar using normal HTML links to ensure that every page of the website is traced by search engines. This type of navigation bar helps crawlers extract more information about the structure of the website than graphic elements. The structure of the website has to be clear as mentioned above in order to minimize the directory depth. Ideally the structure consists of less than four layers. This type of structure is achieved by embedding the most important pages, links, and titles from the second and third layer into the home page.
Social media support: It is widely known that most people use social media daily and it is the only source of information for some of them. Connecting a website to social media accounts ensures that the website gains more traffic as well as quality backlinks which increase its authority. Based on these facts, search engine algorithms begun to depend increasingly on bookmarks, social signals, and the impact of content creators on social media to assess the value of a website.
Custom 404 page: Web Servers return a 404 webpage when the requested webpage cannot be found. Customizing the 404 page helps keep users on the site and can even enhance their search experience. The customization includes pointers to home page or other pages of the site and even references to other sites with relevant to the user’s search content.
SSL certificate: The acronym SSL refers to the term secure socket layer. It is a protocol that establishes an encoded link between the server and the browser that allows sensitive information to be transmitted securely. The SSL certificate ensures that a website is reliable and that the user’s data are kept safe. In addition, it prevents spamming. The websites that have this certificate installed use the protocol https instead of http. Such websites tend to rank higher in the search results as they are safer than similar sites without the certification.
Sitemap xml file: An XML file that is created by the web developer of the website and is submitted for use by search engines. The creation and the uploading of a sitemap along with the website help the crawler to find all the subpages of a website. It also notifies the search engines for any changes made to the website, the degree of significance of every page, the frequency of the website updates, and other information. In sum, it contains information that enhances the effectiveness and the relevance of the indexed website’s content but also makes it easier for search engines to index the website. This procedure is crucial for the optimization of a website as the number of a website’s pages is highly correlated to the website’s ranking.
Domain age: The age of a domain name is quite an important factor affecting the ranking of a website. According to Google’s algorithms, the older the domain the more reliable the website that the domain points to. It is no surprise that websites with newer domains tend to rank lower that those with older ones.
Responsive layout: According to a 2014 study on the subject “Mobile path to Purchase” by Telemetrics and xAd [15
], 50% of the respondents use a mobile device to start their search and two out of three buyers purchase goods and services through their research. Even though there is clear evidence that the mobile devices contribute to e-commerce success, many websites are not responsive to mobile devices. A responsive website not only enhances the experience of the user but also contributes to higher rankings. When making a website responsive, services that mobile devices introduced such as voice search must be considered. It is important to optimize the keywords in order to allow search using whole sentences instead of keywords.
W3C validation: W3C or the World Wide Web consortium is a worldwide web commission. This commission sets some standards regarding syntax errors in the source code of the website. Every website that meets the standards that the consortium sets ranks higher in the search engines. Websites which are validated can add a small icon that indicates that they are w3c validated.
Bounce rate: The metric that shows the percentage of visitors that leave the website just after they view the first page of the website without exploring other pages. Low bounce rate indicates a website with high quality content which is also relevant to the user’s search. That is why search engines recently included that metric as a factor that affects the ranking of a website in the search results.
Time on site: The total duration of a user’s visit in a website. It is obvious that the more time a user spends on a website the more valuable the content of the website is for the search engines as it is more likely for a visitor to spend more time on a page with valuable for them content. Considering the usefulness of this metric, it is becoming an increasingly more important indicator for the ranking of a website.