The WordPress Loop

How do you understand the WordPress Loop and how would you use it to display a list of blog posts?

Where HTML and CSS code can be stagnant, PHP and loops can add a live and variable element to the code. For example, if I have a list of blog posts, I may want the first post to display differently to the rest. I can choose to have it display more text of the blog post, with a picture, where as the other posts will have a limited excerpt and no picture.
I could also use the readers time or location to display different content dependent on if they are reading it in the morning or evening, Australia or over seas.This will make the reader feel as though the site is more personalised to them, and can also be used to show them more relevant content.