Search engine optimization (SEO) is the art and science of getting pages to rank higher in search engines such as Google. Because search is one of the main ways in which people discover content online, ranking higher in search engines can lead to an increase in traffic to a website.
In Google and other search engines, the results page often features paid ads at the top of the page, followed by the regular results or what search marketers call the "organic search results". Traffic that comes via SEO is often referred to as "organic search traffic" to differentiate it from traffic that comes through paid search. Paid search is often referred to as search engine marketing (SEM) or pay-per-click (PPC).
Search engine optimization is a key part of online marketing because search is one of the primary ways that users navigate the web.
Search results are presented in an ordered list, and the higher up on that list a site can get, the more traffic the site will tend to receive. For example, for a typical search query, the number one result will receive 40-60% of the total traffic for that query, with the number two and three results receiving significantly less traffic. Only 2-3% of searchers click beyond the first page of search results. Thus, even a small improvement in search engine rankings can result in a website receiving more traffic and potentially business.
Because of this, many businesses and website owners will try to manipulate the search results so that their site shows up higher on the search results page (SERP) than their competitors. This is where SEO comes in.
Search engines such as Google use an algorithm or set of rules to determine what pages to show for any given query. These algorithms have evolved to be extremely complex, and take into account hundreds or even thousands of different ranking factors to determine the rankings of their SERPs. However, there are three core metrics that search engines evaluate to determine the quality of a site and how it should rank:
Links - Links from other websites play a key role in determining the ranking of a site in Google and other search engines. The reason being, a link can be seen as a vote of quality from other websites, since website owners are unlikely to link to other sites that are of poor quality. Sites that acquire links from many other sites gain authority (called "PageRank" in Google) in the eyes of search engines, especially if the sites that are linking to them are themselves authoritative.
Content - In addition to looking at links, search engines also analyze the content of a webpage to determine if it would be relevant for any given search query. A large part of SEO is in creating content that is targeted towards the keywords that search engines' users are searching for.
Page structure - The third core component of SEO is page structure. Because webpages are written in HTML, how the HTML code is structured can impact a search engine’s ability to evaluate a page. Including relevant keywords in the title, URL, and headers of the page and making sure that a site is crawlable are actions that site owners can take to improve the SEO of their site.
The search engine optimization process involves optimizing each of these core components of search engine algorithms in order to rank higher in the search results.
Understanding how search engines work is only the first step of the process in improving a site's search rankings. Actually improving a site's rank involves leveraging various SEO techniques to optimize the site for search:
Keyword research - Keyword research is often the starting point for SEO and involves looking at what keywords a site is already ranking for, what keywords competitors rank for, and what other keywords potential customers are searching for. Identifying the terms that searchers use in Google search and other search engines provide direction on what existing content can be optimized and what new content can be created.
Content marketing - Once potential keywords are identified, content marketing comes into play. This can be updating existing content or creating brand new pieces of content. Because Google and other search engines place a premium on high-quality content, it's important to research what content is already out there and create a compelling piece of content that provides a positive user experience and has a chance of ranking higher in the search engine results. Good content also has a greater chance of being shared on social media and attracting links.
Link building - Because links from external websites (called "backlinks" in SEO parlance) are one of the core ranking factors in Google and other major search engines, obtaining high-quality backlinks is one of the main levers that SEO has. This can involve promoting good content, reaching out to other websites and building relationships with webmasters, submitting websites to relevant web directories, and getting press to attract links from other websites.
On-page optimization - In addition to off-page factors such as links, improving the actual structure of the page can have tremendous benefits for SEO, and is a factor that is entirely in the control of the webmaster. Common on-page optimization techniques include optimizing the URL of the page to incorporate keywords, updating the title tag of the page to use relevant search terms, and using the alt attribute to describe images. Updating a page's meta tags (such as the meta description tag) can also be beneficial-- these tags don't have a direct impact on search rankings, but can increase click-through rate from the SERPs.
Site architecture optimization - External links are not the only thing that matters for SEO, internal links (the links within one's own website) play a large role in SEO as well. Thus a search engine optimizer can improve a site's SEO by making sure key pages are being linked to and that relevant anchor text is being used in those links to help improve a page's relevance for specific terms. Creating an XML sitemap can also be a good way for larger pages to help search engines discover and crawl all of the site's pages.
Semantic markup - Another SEO strategy that SEO experts utilize is optimizing a website's semantic markup. Semantic markup (such as Schema.org) is used to describe the meaning behind the content on a page, such as helping to identify who the author of a piece of content is or the topic and type of content on a page. Using semantic markup can help with getting rich snippets displayed in the search results page, such as extra text, review stars and even images. Rich snippets in the SERPs doesn't have an impact on search rankings, but can improve CTR from search, resulting in an increase in organic traffic.
As a fairly technical discipline, there are many tools and software that SEO relies on to help with optimizing websites. Below are some commonly used free and paid tools:
Google Search Console - Google Search Console (formerly known as "Google Webmaster Tools") is a free tool provided by Google, and is a standard tool in the SEO's toolkit. GSC provides rankings and traffic reports for top keywords and pages, and can help identify and fix on-site technical issues.
Google Ads Keyword Planner - Keyword Planner is another free tool provided by Google, as part of their Google Ads product. Even though it is designed for paid search, it can be a great tool to use for SEO since it provides keyword suggestions and keyword search volume, which can be helpful when doing keyword research.
Backlink analysis tools - There are a number of link analysis tools out there, the two primary ones being AHREFs and Majestic. Backlink analysis tools allow users to analyze which websites are linking to their own website, or the websites of competitors, and can be used to find new links during link building.
SEO platforms - There are many different SEO platforms that bring together many of the tools that SEO needs to optimize sites. Some of the most popular include Moz, BrightEdge, Searchmetrics and Linkdex. These platforms track keyword rankings, help with keyword research, identify on-page and off-page SEO opportunities, and many other tasks related to SEO.
Social media - Most social media sites don't have a direct impact on SEO, but they can be a good tool for networking with other webmasters and building relationships that can lead to link building and guest posting opportunities.
Search engine optimization done properly can have the potential to dramatically increase the amount of traffic that a website receives, but all of that search traffic won’t help grow a business unless it converts into paying customers. This is where conversion rate optimization (CRO) comes in.
Conversion rate optimization involves using methods such as A/B testing to make changes to websites and measure the impact they have on a site’s conversion rate. Successful search marketers know that just getting traffic to a site is not enough, what the traffic does once it arrives on the site is just as important.