SMASHDOCs - Web application for easily and quickly writing and reviewing documents within or between enterprises.
Just Social - JUST SOCIAL provides all the collaboration tools like enterprise social network, real-time document collaboration
Slite - Your company knowledge
Dropbox Paper - A collaborative document-editing service
IntraLinks VIA - Intralinks VIA is a solution for secure and compliant enterprise content collaboration across boundaries.
Google Drive - Access and sync your files anywhere