Understanding CSS Comments

Comments are an integral part of any programming language. In CSS (Cascading Style Sheets), they serve the same purpose of improving code readability and making it easier for others (or even for the author at a later stage) to understand the code's structure and purpose.

The correct way to add a comment in a CSS file is using the /* this is a comment */ syntax. The opening comment tag is /* and the closing tag is */. Anything placed between these two comment tags is considered a comment and is ignored by the CSS parsing engine.

Let's consider an example CSS file:

/* This is a global CSS file */
body {
  /* Setting the background color to white */
  background-color: #fff;
  
  /* Setting the text color to dark gray */
  color: #333;
}

In the above example, there are several CSS comments explaining the purpose of the CSS rules.

CSS comments can be used in various ways to enhance the understanding of your code:

1. Code Descriptions - Briefly describe what a piece of code is meant to do.
2. To Do Lists - Highlight what CSS changes or additions are pending.
3. Annotation - Explain why a specific piece of code is written in a certain way.
4. Debugging - Temporarily remove a piece of CSS code from being interpreted by the browser. This is useful when you are unsure of a code snippet's effects and wish to isolate its impact.

On the other hand, it's important to note that CSS comments should not be overused to the point where they clutter the code. It's about striking the right balance between explanatory comments and clean, readable code.

Also worth noting is that the other represented ways of commenting like // this is a comment, // this is a comment //, and <!-- this is a comment -->, while they might work in some other languages like JavaScript or HTML, are not acknowledged by CSS and would result in either ignored comments or potential syntax errors.

In conclusion, using the /* this is a comment */ syntax correctly to add comments in a CSS file is an effective way to annotate your code and improve its long-term usability.