To allow authors to workshop their writings and at their discretion allow them to be shown on the internet. You can also maintain your own profile and upload any of your poems.

Only if you change the poems status to publish, otherwise it's only viewable to others authors that you have specifically allowed.

When an uploaded poem is viewed the uploaded file is displayed in a new window, therefore it's best to save your poems as a web page. For example, using Word you can save as type Web Page (*.htm, .html) and upload that saved file.