HTML is a very primitive but portable language. The main benefit of this is that it enables many people across many different computer platforms to look at basically the same presentation.
However, remember that people can have all kinds of preferences set on their browsers to control what they see, and as a result you cannot predict how anyone else will see your work. For example, they might see one paragraph of it at a time, or several. They might be able to load graphics quickly or not at all, or type that looks gigantic to you on the screen might appear much smaller to someone else.
For now, you should concentrate on the main message of your text. When we get to graphics, we will discuss how to keep them small in file size and reduce colors to make it easier and quicker for people to view your work on-line.
There are more advanced forms of HTML in the works, but not all browsers can interpret the newer codes. So, to keep your work readable by the largest audience possible, it is best to stick with the basics.