In this guide, we will focus on the main tools to search for information on the Internet or, better said, the Web.
Yes, because the Internet and the Web are not the same things, as this video reminds us:

If you want to know exactly what is the Internet, what is the web, and what lies ahead in the immediate future, you can read this interesting article in the Treccani online Encyclopedia.

Back to our guide, we will focus on web search engines, especially Google and its two specialized features: Google Scholar and Google Books. Then we will take a look at some social networks meant for the scientific community and very popular among researchers.
So let's start with a video that briefly explains what search engines are: 

Have you watched the video carefully? 
Have you noticed that among the other topics covered it talks about the criteria of trustworthiness, that is reliability attributed by search engines to websites?  
Keep it in mind and compare it with the one developed in the guide "The evaluation of sources and the risk of plagiarism"
The trustworthiness parameter attributed by search engines automatically, and the one we talk about within the scientific community and that you are supposed to use when you evaluate a document (a website or a book or any other source of information) are very different.
Warning: this does not mean that we do not have to use search engines. They are essential, we could not do without them searching through millions of web pages available. However, it is important to be aware of the way they work so that we can make correct evaluations and take the right decisions.
There are many search engines, here you can find an approximate list.  In the next pages, we will look in particular at Google and its features.