Useful definitions to understand SEO

seo-definitionsDefinitions to understand SEO

This page will provide some useful definitions to help you understand SEO, i.e. how you can optimize your professional website.

You will be able to prevent scams about SEO as the definitions below will give you a complete understanding regarding SEO.

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What is Internet?

“Internet” is an English word formalized on January 1, 1983.

This is the “network of networks”, now globalized, which is based on Packet Switching technology, as opposed to communication networks based on Circuit Switching Technology used previously, mainly for telephony and fax.

Packet Switching Technology was invented in 1950 by Louis Pouzin, a French engineer graduated from Ecole Polytechnique.

Packet switching is a digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably-sized blocks, called packets.

This invention inspired the research initiated in 1967 by the United States under the project named ARPANET. Several researchers worked on this concept and created a comprehensive and reliable communication system based on Packet Switching.

Stanford University graduate, Vinton Cerf is prominently known in the United States as the father of the Internet.

These standards are still in use today.

TCP is a protocol that corresponds to a layer of transmission.

TCP gathers the information that controls the reliability and order of receipt for the information packets or datagrams.

IP is the protocol of the network layer address that allows for a single address for all connected terminals.

It is a protocol that is not connection-oriented as no path is defined in advance.

It is designed to ensure the best transfer of the information packets or datagrams.

Physically, the Internet consists of interconnected routers that transfer data packets through a system of IP addressing.

In 1980, part of the network that was originally intended entirely for military purposes was transferred to the American Academic World.

This civilian network was quickly adopted as means of communication between researchers, academics and students worldwide.

Later, in the 1990s, connections to the Internet at low speed were offered to the general public.

Now widely available thanks to broadband connections, the Internet has become a communications network used by hundreds of millions of people around the world every day.

The Internet is a hierarchical network with IANA as the top authority on the network. This organization manages the port numbers and IP addresses.

Under the IANA, there are four organizations that cover the four major population groups in the world, designating the NIR for each country:

  • APNIC which manages the database of IP addresses for the Asian and Pacific area.
  • ARIN manages the database of IP addresses for North America and Sub-Saharan Africa.
  • ACNIC that manages the database of IP addresses for South America and the Caribbean Islands.
  • RIPE that manages the database of IP addresses for Europe, Middle East, Central Asia and African countries located in the northern hemisphere.

On the third level of the hierarchy are the Autonomous Systems.

They receive the IP addresses from the corresponding regional database.

Autonomous Systems are operators who have their own network and manage their own routing policy and connectivity.

On the fourth level of the hierarchy of sharing IP addresses are the Internet Service Providers that offer services to the public.

Sometimes, as in China, the regional branches of Autonomous Systems Operators play the role of Internet Service Provider.

The Internet Service Providers receive groups of IP addresses from an Autonomous System.

The fifth and final level of the hierarchy is the end user who receives their IP addresses to connect to the Internet.

What is the Web?

On the basis of transport and addressing protocols, TCP/IP and other protocols related to applications have been implemented; the most famous of these applications is the Web.

The Web application, which includes the communication protocol HTTP and the HTML was invented by the Englishman Tim Berners-Lee with the assistance of the Belgian Robert Caillaud in the early 90s.

These inventions are free of copyright.

The World Wide Web, commonly called Web, gathers all the webpages by a web address starting with http.

This application is based on a communication protocol called HTTP added on the top of the layers of addressing and transport TCP/IP.

Clients of this application are Web browsers (Internet Explorer, Firefox, Chrome, Opera, Safari …) allowing a final user to access a server containing data easily.

Another application of the Internet is email.

Email flow is managed by another protocol layer consisting of three communications protocols related to this application:

  • SMTP is dedicated to sending messages
  • POP is used to retrieve messages for playback
  • IMAP can synchronize both, including the sending function, receiving function, but also erasing and classifying email functions

What is a Professional Website?

A professional website is a publicly accessible folder using a web address that begins with “http://”.

This folder contains all of the html files that organize the texts and pictures of a web page.

Today there are hundreds of millions of business websites in the world.

In September 2010, there were over 227 million active websites worldwide.

Source: Netcraft

The key to the success of your professional website is to gain visibility among the hundreds of millions of other professional websites.

What is a Domain Name?

A domain name is a memorable and meaningful string of ASCII characters pointing to an Internet IP address whose format is a sequence of numbers with dots that are difficult to remember.


Domain names can have several levels; each level is defined by a dot in the domain name.

A domain name with a single extension is called TLD (Top Level Domain).

A generic top level domain name is called a gTLD.

Examples of generic top-level extension:

  • .aero (Air Transport)
  • .asia (Asia-Pacific Area)
  • .biz (Business)
  • .com (Business Organization)
  • .edu (Educational Institution)
  • .gov (Government Agency)
  • .net (Network of Operations Center or Information Centers)
  • .info (Information)
  • .org (Organization)

At the first level, there is also the ccTLD (country code Top Level Domain) which are the official country code domain names: .fr, .eu, .us, .cn…

It is possible to define sub-domains from an existing domain name, creating new web addresses.

For example, is a subdomain of and is a full web address.

In China, as it was not possible to use Chinese characters, many domain names consist of a combination of letters and numbers.

In China, the figures are traditionally meaningful. For example the 6 indicates luck, the 8 denotes money.

Top-level domain names are sold by registrars.

A registrar is a company whose business is booking Internet domain names.

Each registrar proposes to register domain names with one or the Top Domain Name extensions: .com, .us, .cn, etc.

What are Hosting Services?

To have a professional website accessible on the Internet – to make it available 24 hours a day, 7 days a week – you need a computer connected to Internet all the time with a very high speed connection and with a system accessible from the Internet.

The folder containing your website has to be recorded on a computer called a Server.

The computer system directly accessible to the Internet as the most popular, free and very reliable is called Linux with the web server software Apache.

Different types of Hosting services are available on the market; limited or unlimited in volume and in bandwidth.

All hosting services available from the Aellio Web Agency are unlimited; hosted on highly secure servers and connected to the Internet with a high access rate reaching 99.9%.

What is a Url?

URL is an acronym which means Uniform Resource Locator.

This is a unique string that begins with http:// and consists of ASCII characters to define the path to a single file on the Internet.

URL is synonymous with web address.

What is a Sitemap File?

A Sitemap file describes the layout of your professional website to Google.

It allows for fast and complete indexing of all web pages on your professional website by Google.

It also lets Google know the last modification date of each webpage on your professional website.

To verify if a website has a sitemap, just add “/ sitemap.xml” to the end of the address of a professional website.

This file is generated automatically by the Aellio Web Agency for all websites created or optimized by the Aellio Web Agency, including professional websites created with the Aellio Content Management System.

Here is the file sitemap.xml related to Aellio Professional Website: Aellio Website Sitemap under XML format

What is HTML?

HTML is an acronym that means “HyperText Markup Language”.

HTML lets you create web pages.

HTML gives structure to texts and creates links between files that may be other web pages, but also all kinds of downloadable files such as computer programs, text, images, videos and music).

Having evolved since the 90s, HTML has stabilized over the past ten years under its version 4.

Version 5 has been defined but is not wide spread.

HTML is composed of about 90 different tags used to structure a web page, but only a few dozen of these tags are commonly used.

Each tag includes parameters to define its content or its layout.

HTML tags are visible in the webpage source code.

HTML tags allow for text structure: titles, subtitles, paragraphs and insert elements inside pages such as images, videos and links to other files.

Most tags are opened and closed using the following syntax: <HTML-tag-name>Tag content</HTML-tag-name>

Some exceptions exist, such as image tag img used to insert pictures: it opens and closes in a single tag.

In this case, the tag syntax is: <img src=”image-web-address” />

The src parameter in the img tag indicates the path to the image file to display.

Each web page has two main parts:

  • The header includes information that is not intended to be displayed and which are grouped at the top of the source code of the web page within a tag <head>.
  • The body of the webpage that contains the elements to be displayed in a <body> tag.

Here are 5 basic HTML tags that are useful to know in order to create your own web page content:

  • The p tag defines a paragraph.
  • The h1 tag, stands for Headline. It defines a first level headline. For the second and third level titles, there are h2 and h3 tags.
  • The img tag, short for image: it allows you to insert an image on a web page. A required parameter for this tag is src tag which gives the path to the image file to display.
  • The a tag defines a hyperlink to another file: it is essential because it helps create links between existing web pages and to any kind of multimedia files. The mandatory parameter of this tag is href which gives the path of the file reached by clicking the link.
  • The ul tag means Unordered List and is always associated with the li tag to separate each element of a list.

Other tags are very useful for defining the webpage’s layout:

  • The br tag to force a carriage return
  • The hr tag to draw a large horizontal line
  • The div tag to create a rectangular block
  • The span tag to apply a style to some text
  • The quote tag to give a specific citation style
  • The table, tr and th tags to create tables

Finally, there is another group of HTML tags used to create online forms.

Such forms require a computer processing at the server in order to save the data in a database or in order to generate emails gathering data provided by the visitors.

The Aellio Content Management System automatically creates the HTML code for your website through an interface similar to Microsoft Word.

The Aellio Content Management System gives you full access to the HTML code, thanks to a HTML function button.

This allows advanced users to edit the HTML source code, adding interactive programs (widgets) to obtain a 2.0 website.

The Aellio Web Agency can create any kind of online form you may need.

The Aellio Web Agency also offers a standard form in the Aellio Content Management System to send email messages to your website’s visitors.

What is a HyperLink?

A HyperLink, also called a hypertext link or simply a link, is a reference from a web page to access another web page or to any kind of file by clicking on text or on an image.

The HTML tag that defines a hyperlink is a.

Each HyperLink tag has a mandatory parameter called href to define the web address of the destination page.

Example of a link in HTML: <a href=”” >This is the link text</a>

There are 2 types of HyperLinks:

  • Internal Links: links that let you move from one webpage to another webpage inside the same website.
  • External Links: links written on another website’s webpage that point to a webpage on your professional website. These links are particularly important for improving the position of your professional website in Google search results.

Thanks to the links between the different webpages of different websites, your webpages can receive new visitors even if those visitors did not know about you before.

It is because of this basic principle that you can improve your website’s ranking.

Receiving links from other websites will generate more traffic, making Google recognize your website as a important website.

Google scans the links between websites and uses the number of links between websites associated with the text of those links as a key criterion to generate search results lists.

What is MetaData?

Metadata are pieces of information used to identify and classify a document.

Each web page contains metadata used by Google to classify and identify them.

Metadata is invisible when viewing a webpage normally.

Metadata is sometimes called Hidden Data.

Metadata is only visible when you access the source code of a webpage.

Metadata is stored in the header of each web page in the tag that defines the header of a web page: <head>

Each webpage has 3 important metadata components regarding Google indexing:

  • The Webpage Title
  • The Webpage Description
  • The Webpage Keywords

The Aellio Content Management System gives direct and simple access to these 3 metadata components.

What is PageRank?

Pagerank is the rating given by Google to every webpage on the Internet.

The public PageRank of a webpage is an integer between 0 and 10.

To find the complete rules of calculating PageRank Google: Full explanation of the calculation of PageRank.

What you need to understand about PageRank optimization:

  • The more links a webpage receives, the higher the PageRank, especially if the links are coming from other websites.
  • The more links a webpage has to other websites, the lower the PageRank.
  • The PageRank of the webpages with links to your webpage and the number of other links on each of these web pages are important factors needed to calculate PageRank.

The Aellio Web Agency has mastered the rules for calculating PageRank, allowing us access to a very effective optimization strategy.

To know the PageRank of a professional website, several online tools are available to show your public PageRank for free.

Warning: many of these free tools give false results.

Here is a tool showing your correct public PageRank (last checked: January 2011): Access to PageRank Tool

The actual PageRank is calculated by Google for all public web pages about once a week, and the public value of the PageRank of a webpage is issued about three months later.

Basically, the public value of a webpage PageRank is different from its actual value.

The public value is a rounded figure, while the real PageRank number has digits after the decimal point.

PageRank is an important factor for ranking webpages in the search results on Google, but it is far from being the singular criteria.

The content quality, especially the quality of the text, is equally important in determining the PageRank.

What is SEO?

SEO is an acronym that stands for Search Engine Optimization.

Optimization is vital for a professional website to gain visibility on the Internet.

You literally need the thousands of people who search for keywords related to your business in Google to find you easily.

This means that your business website should be on the first page of search results for the effective keywords related to your business.

Otherwise your professional website cannot bring you new customers.

To successfully optimize your professional website for Google:

  • Accurate selection of effective keywords from the beginning
  • Maximize the use of HTML/CSS and minimize the use of Flash because Flash is transparent for Google and it does not appear on the iPhone
  • Give fixed web addresses (URLs) to each page with effective keywords inside the URL name
  • Have quality content, i.e. texts long enough on each page and well structured texts with titles, subtitles, paragraphs and lists
  • Benefit from external links from web pages with high PageRank and with low number of external links
  • Properly manage the metadata of each web page of your professional website
  • Having an up-to-date XML sitemap file

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