Dr.Explain - Dr.Explain software is a help file authoring tool.
Airim - Show personalised FAQs before live chat
MadCap Flare - Documentation for Any Audience, Language or Format
HelpSite - HelpSite is a simple service to help your setup the perfect support centre or help site.
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
Manula - Manula is an online software for creating user manuals.