To each his own address

We were left with links: the words that, if you click on them or touch them, take you somewhere else.

Do an exercise: try scrolling this page from top to bottom and count them. Pay attention that not all links are underlined. There are many ways to make it clear that a word is a link: sometimes you recognise them because they have a different colour from the surrounding text, other times you recognise them because they are where you expect them to be. Go ahead, count them, I'll wait. No rush, just curiosity to understand.

Here we go. How many links have you counted?

Not all links are the same, even if they seem to be: some take you to other pages of the site you are on, others take you to other sites. Put like that, it seems like a minor thing. However, if we go back to the analogy between books and sites that I was telling you about last week, you will soon realise that the power of this mechanism is enormous.

For example, there are 'links' that you find in almost every book: they are the index entries. They link to other pages and make you jump around. You stop, browse, look up the page and start reading again. They are-let's say-internal links. There are also links between different books: for instance when an author quotes other books or passages from other books. Here: these are external links. In these cases, in order to go deeper, you have to at least get up, go and get the other book, leaf through it, find the right page and, then, you can start reading again.

Links on the internet, on the other hand, all work the same way: you click or tap on the word and, zoing!, you are already at your destination. All magic hidden in your smartphone!

At this point you are probably wondering (and if you're not wondering, let's pretend you are wondering): "But if everything is so easy and so fast, and I can move from one place to another on the net with just a few clicks, how do I keep up?"

Easy: the address tells you. When you use the Internet and visit a site, there is always an area (usually at the top of the screen) where you see an inscription full of strange characters, like www.sistrall.it. That is an Internet address and there is a lot of information in there. I'll tell you a little at a time, in strict order, but let's start with this one: all pages of a site have an address that starts with the same 'words'. Pay attention to this: all the pages on my site begin with / or something similar (if you read with your phone, you will probably only see www.sistrall.it, which is the most important part, and the phone highlights it for your convenience).

So, the summary of this episode is:

• if you click on a link and the address always starts with the same words, then you are always on the same site;
• if you click on a link and the address changes a lot, then you have ended up on another site.

That's enough for today, the train is coming and I have to get off.