What is a SEO? Digital Challenge for dummies

For people in the business it's an obsession, for the uninitiated an acronym that hides who knows what mystery.
What are we exactly referring to when we speak of SEO?

Meaning

SEO stands for Search Engine Optimization, and refers to the range of practices used to improve a web page's visibility with regard search engines.

Why is it important

Most users reach sites by making a request on a search engine: it's therefore essential that a site's content be indexed in their databases.
SEO is therefore essential for both the owners of a site and internet users. For those who have a web site an appropriate positioning of their web site with search engines improves incoming traffic numbers: the results are higher up in the search engine answer page get more clicks. For those who surf the web it's important because it offers more likelihood of finding exactly what you're looking for.

So what does a SEO do?

Research engines are constantly updating their own technology to provide increasingly pertinent results to the queries they receive. To make sure you're on the first page of a search engine you have to optimize certain internal and external aspects of a site.
The internal activities include the optimization of the HTML code and the structure of the site, the text content and the images. The external activities instead concern the quantity and quality of the connections to other sites.

The SEO's work can be very extensive, and its applications are virtually infinite. That's why a good SEO can make the difference between a site with little appeal and one that enjoys great 'web' success.