<!-- --> creates a space for comments

The comment tag creates a space in your HTML document for content that won't appear on the page itself. Since everything inside the comment tag remains hidden, you can use it for personal reminders or notes to friends. But be careful there, hotshot: Comment tags are visible to anyone who views your source code. If you hide your deepest, darkest secrets there, someone's likely to see it.

Comment tags look like this:

<!--Eric, keep your comments to yourself.-->

We'd show you what it looks like, but, um, it's hidden. You'll have to take our word for it.