HelpScout - Help Scout is a simple, straightforward way to provide excellent support

GrooveHQ - A new and better way to support your customers. 8,000+ companies provide personal support at scale with Groove’s Shared Inbox, Knowledge Base, and Reports. All without breaking the bank.

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

Salesforce Service Cloud - Service Cloud integrates customer service with social networks and provides a self-service customer portal and knowledge base system.

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

Front - The platform for exceptional customer service at scale.