InStream CRM - Business relationship management platform - CRM alternative
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
Gmail CoPilot by cloudHQ - Easy CRM: View all past conversations with an email contact
Salesforce Service Cloud - Service Cloud integrates customer service with social networks and provides a self-service customer portal and knowledge base system.
Crmble - Easy peasy crm for Trello
Zendesk Support - Social Customer Support and Help Desk and Ticketing