Worst of all the only way to share the document with someone is to send him the link to sribd, indirectly promoting them. It's not that I want to, but it's too painful to source the "original" source of that file once it's inside of scribd. The fact that they force you to sign up to download the document sure helps to build up the wall too.

Seems like the platform is viral as such. Not viral as in alpha geek, but viral as in HIV.