FileProInfo - It's All About Files, Software, Online Tools - 100% Free
MadCap Flare - Documentation for Any Audience, Language or Format
File-Extensions.org - Large computer file extension library with detailed explanation of each file type with links to download free or associated software programs.
Yumpu.com - The UK’s favourite all-inclusive online magazine package
GroupDocs - GroupDocs is a web-based service for online document sharing, collaboration and management.
Readymag - Readymag is a design toolkit that helps create immersive digital experiences without developers in days, not weeks.