Your documents are automatically set to be viewed by anyone whom you have provided the link to. Clicking on the arrow next to the “share” button allows you to view the link and to make changes to the sharing features. Current settings do not permit documents from this service to be published on the web.
You may also share the contents of entire folders in Google Docs in the same fashion.
You can then set who you want to share your document or presentation with and if they have permissions to just view the document or permissions to make changes as well.