Amplification helps raise the Volume level. In Audacity, setting the level to 0.0 will bring the audio as high as it will go without clipping.
When creating a podcast, audio story and especially for Radio Programming; Amplify helps to bring audio levels for finalizing a show to share with the world.
Here is an example of using amplify on vocal dialogue.
This is a project in part by Kulshan Community Media and the Whatcom Community Foundation.