PDF Submission is another way of creating quality backlinks for the purpose of SEO and Online Marketing. PDF Submission Sites Play important role in your Website SEO when your Documents are informational, interesting and readable. Because people share the docs with each-others when they find it knowledgeable and interesting.
While creating files for submission on Free PDF Submission sites or Document sharing sites, keep in mind that your documents would be informational, unique and shareable.
List of Document Sharing Websites