What are headlines and taglines?

Before jumping into this post, it might be useful to explain what headlines and taglines actually are. Wikipedia explains a headline in the following way:

The headline is the text indicating the nature of the article below it.

So the headline is basically a page’s or post’s title. And as Wikipedia so eloquently states it; that title should indicate what that page or post is about.

And Wikipedia explains the tagline as follows:

In entertainment, a tagline (or tag line) is a small amount of text which serves to clarify a thought for, or designed with a form of, dramatic effect.

I don’t completely agree with a tagline being for dramatic effect, but I do agree with the fact that a tagline serves to clarify a thought. Usually, it serves to clarify or specify the headline. A tagline is also something that’s not as mandatory as the headline. A page has to have a headline, but it doesn’t have to have a tagline. Especially not if the headline is clear enough in itself.