StickyNoted - Sticky Note with Markdown flavour

UserVoice - UserVoice integrates easy-to-use feedback, helpdesk, and knowledge base management tools in one platform that empowers users to speak and companies to understand.

Usersnap - Usersnap is a customer feedback software for SaaS companies that need to constantly improve and grow their products.

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

Sticky Notes - Sticky Notes is an integrated feature of adding notes in the Windows operating systems.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.