Update Mar 23, 2011: From now on I will not provide warnings if the steps outlined here are not followed. Items will simply be deleted as soon as I see them. This gets really old people.

I want to stress to people uploading items to make sure you go back and edit the item you've uploaded to include a more complete description, keywords, summary, etc. But more importantly, to fill out the Usage field. You can find this field on the Custom Fields tab as you're editing your item. Select either Personal Only, or Personal and Commercial. These values tell how your uploaded item can be used, a very important thing! Protect your copyright!