What are some alternatives?
When comparing Helpie Knowledge Base Wiki Plugin and HelpJuice, you can also consider the following products
MediaWiki - MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia.
Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
DokuWiki - DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn't require a database.
Bloomfire - Let Bloomfire help you get organized! Organize your content, build your company knowledge base and help your employees to be more successful.
AMuseWiki - Amusewiki is more than just a wiki engine, it’s also a powerful authoring, archiving and publishing platform.
ZenDesk - Zendesk is a beautiful, lightweight help-desk solution.