The example given contained three simple tags.
The H1 tag means "top-level heading". It is used to mark the most important title on a page. As you saw, the text marked within the H1 was shown by the browser as a large heading. (H1 is not always displayed like that; H1 simply indicates that the text is an important heading, and the large serif font that appeared is the default font for important headings. We'll see how to change the display of page elements, including headings, in a later class.)
The P tag means "paragraph". Paragraphs are very important in HTML. Each paragraph of text should be contained within P tags.
If you look at the source of the example, you may notice an interesting fact: the additional spaces and line breaks included in the source were completely ignored. When you put more than one space or line break between words, HTML ignores this and treats it as a single space. So to divide text into paragraphs, you need to use the P tag; hitting return a few times will have no effect.
The TITLE tag is used to assign a title to the page. This title will be used wherever a Web browser (or sometimes another Web site, for example a search engine) needs to display a title for a page.
For example, titles appear in the browser's title bar. If you bookmarked the example page, the bookmark would also be labelled with that information from the title tag.