SEO: what optimization is and how it works (2021) For education

SEO is the branch of Digital Marketing that deals with improving the position of web pages in the organic (non-sponsored) search engine results. In this guide we will see in detail what it is and how it works.

SEO: Definition and meaning

SEO is that set of strategies and practices aimed at increasing the visibility of a website by improving its position in the rankings of search engines , in the unpaid results, called ” pure ” or ” organic ” results. SEO is an acronym (acronym) that stands for Search Engine Optimization , literally translated: ” optimization for search engines “.

These practices are manifold and concern different aspects of a website: the optimization of the site structure, the HTML code, the textual content, the management of incoming links (i.e. that from other sites point to your site, called inbound links or, more commonly, backlink
A backlink is a link from any website to our site. Search engines like Google use backlinks as a signal to …
) and outbound (which point to others from your site).

Since Google is by far the most used search engine in the world , most of the SEO activities concern the study of the Google algorithm and its periodic updates , and the related actions to make the sites more “welcome” to this algorithm. 

SEO explained to a 6 year old child

When we search for something on search engines, we expect to find the best results first, that is, those most relevant to our search. For example, if I search for “3-star hotel in Bologna”, I don’t want to find the site of a bed and breakfast in Naples. And I also want to find a lot of information about that hotel, like what the rooms are like, how much it costs, where it is, etc. SEO therefore means first of all writing rich and relevant content with the words we want to be found with.
Links are the “roads” of the web , ie the paths we use to move from one site to another. A site with many links leading to it is like a very busy intersection, therefore very important . And – just like in cities – the more important the site that links to us is and similar to ours in content, the more comfortable the road that leads to us will be. For this, doing SEO also means trying to get a good number of links from sites that are as relevant and relevant as possible.


SEM stands for Seach Engine Marketing (marketing through search engines) and is the broader discipline that incorporates SEO. SEM includes both paid search results (where you can appear using tools such as Google Adwords or Bing Ads, formerly known as Microsoft adCenter) andorganic results
Organic results are preview lists of web pages that appear as a result of the search engine algorithm, and are not paid. The…
search (SEO).

A complete SEM strategy uses both paid advertising and the implementation of SEO techniques. A keyword analysis is performed for both SEO and SEM, but not necessarily at the same time. SEM and SEO must both be monitored and updated frequently to adapt to evolving best practices.

In some contexts, the term SEM is used exclusively to indicate pay per click advertising, but it would be more correct to call the latter SEA, or Search EngineAdvertising
Advertising (abbreviated ADV) means advertising, it is a paid message that a company sends with the aim of informing or influencing the people who receive it …
(see next paragraph).

Difference between SEO and SEA

An important distinction must be made between search engine optimization and search engine advertising (SEA). SEO differs from SEA in that in the first case there is no direct payment to the search engine to appear in its results. The SEA on Google is carried out through the Google AdWords circuit , the platform that allows you to create sponsored link campaigns , which are marked with the words “Ann.” and are displayed, if present, as the first (maximum 4) and last (maximum 3) results of the page.

The payment mechanism for sponsored links is the PPC
PPC stands for pay-per-click (pay per click), it is a type of advertising in which advertisers pay a figure every time their ad …
(pay per clik) , i.e. the advertiser pays a certain amount every time a user clicks on his link. The amount to be paid, according to the logic of the auction , depends on how much other advertisers are willing to pay, so those who bid more will be higher in the results than those who bid less.

The results unpaid are called results “pure” or “organic” , for this reason, the EES, which does not concern the paid results , it is also said pure positioning or organic . SEO and SEA both fall within the macro-activity of web marketing called SEM , or search engine marketing (marketing through search engines).

SERP: acronym for Search Engine Results Pages, literally “page of the results of a search engine”. SERPs are web pages served to users when …
: “Search Engine Result Page”, literally translated search engine results page, is any Google page that appears after you have entered the term or terms to search for. The image above is an example of a SERP.
Query is usually used to indicate a request that a user makes using a search engine. Whenever we look for something on an engine …
: it is any search carried out on the engine. when you enter one or more words in the Google search field, you are executing a query.
Keywords : “keywords” (or search key), are the words you enter in the search field when you perform a query. By keyword we mean not only single words but also text strings, for example the search “web marketing Bologna” is a keyword.
In computer science, a robot (or simply “bot”) is a set of coded commands or instructions that indicate to a mechanical device and system …
: (also called spider ocrawler
A web crawler, also called a spider or robot, is software that systematically browses the World Wide Web, typically for the purpose of indexing the web. THE…
), is the software that search engines use to analyze all the sites on the network automatically. The robots run continuously to scan the entire network, passing from page to page by means of links. They make a text copy of all the documents visited and insert them in an index (seeindexing
Indexing is the phase in which the search engine collects, analyzes and stores data to facilitate the rapid and accurate search for information 
). The Google robot is called Googlebot
Googlebot is the name of Google’s robot (or crawler). A web crawler, also called spider or robot (or simply “bot”) is software that …
Indexing : is the process by which the robot adds material to thedatabase
A database is an organized collection of structured data to make it easily accessible, manageable and updatable. Put simply, it can be said, a database in …
of its search engine to return it then, sorted in a ranking (see ranking
In SEO, Ranking refers to the position in the ranking of search engines such as Google. Get a good ranking for relevant keywords for …
) based on relevance with the search key, when a query is made.
Ranking : is the ranking of the results with respect to a specific query. When we enter a keyword, the search engine returns a SERP of results sorted according to the relevance of the indexed documents with respect to that keyword. Ranking is also synonymous with positioning (see), in the SEO field it is called ” ranking factor” any element, internal or external to the site, which influences the position in the ranking.
Optimization : in the SEO field, optimizing means making the work of robots as easy as possible, providing them with easily accessible content and making it easier for the software to understand the topic covered by the document.
Positioning : consists in improving the position of a site / web page in the ranking of search engines in relation to certain keywords. Positioning (or improving it) is the natural consequence of optimization.
For other terms, you can check out our SEO dictionary .