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
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Deskero - Deskero is a simple, flexible and social-aware helpdesk software and support ticket system to take care of customer service with a few clicks.
Helprace - Helprace is a customer service software suite linking a ticket system with help desk software, giving customer support agents a complete helpdesk solution.
HelpScout - Help Scout is a simple, straightforward way to provide excellent support
Kayako - Help Desk Software and Customer Service Software by Kayako. Improve customer satisfaction, increase sales.