SLIDESHARE

SlideShareis a site that offers users the ability to upload and share public orprivate presentations of PowerPoint slides, Word documents, OpenOffice, PDF Portfolios. 

The hosting service is free and registered users can access the registry or using your Facebook account. 
But as well, in Slideshare there is a type of registration that allows mores recursers but isn't free.

This digital presentation is posted in Slideshare: 

Click here to go a website.