In this example we have a box with three columns. The first has a heading that starts lower than the paragraph text in the next columns. If we could specify line-height to be applied only below each line, not not above and below the columns can align. This is vital for columns to be used effectly as currently it is impossible to align text correctly.

This is my multi-line heading

Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sed ante quis enim ultrices facilisis. Proin a augue quam, id cursus sapien. Maecenas sit amet leo eget nunc aliquam iaculis et quis elit. Nullam iaculis viverra eros, at viverra tortor iaculis ac.

Nullam blandit pharetra blandit. Sed porttitor mauris ac justo scelerisque malesuada. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam facilisis est vitae urna aliquet interdum. Vestibulum lacus nisi, gravida rhoncus venenatis non, accumsan quis lectus. Duis eu libero a dolor semper ornare at id quam. Morbi blandit, odio quis ultricies ornare, ante nisl tempor odio, ac cursus neque sapien sit amet purus. Sed sodales metus vel neque sagittis eleifend.

This is my multi-line heading set in a different size

Lorem ipsum dolor sit amet, consectetur adipiscing elit. In sed ante quis enim ultrices facilisis. Proin a augue quam, id cursus sapien. Maecenas sit amet leo eget nunc aliquam iaculis et quis elit. Nullam iaculis viverra eros, at viverra tortor iaculis ac.

Nullam blandit pharetra blandit. Sed porttitor mauris ac justo scelerisque malesuada. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Etiam facilisis est vitae urna aliquet interdum. Vestibulum lacus nisi, gravida rhoncus venenatis non, accumsan quis lectus. Duis eu libero a dolor semper ornare at id quam. Morbi blandit, odio quis ultricies ornare, ante nisl tempor odio, ac cursus neque sapien sit amet purus. Sed sodales metus vel neque sagittis eleifend.

Example from Indesign, a leading print layout package. Here we can clearly see columns align correctly.