Cakemail - Email marketing and transactional emails that deliver. Try it for FREE!
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Hatchbuck - SMB sales and marketing software
tawk.to - tawk.to is a free live chat app that lets you monitor and chat with visitors on your website or from a free customizable page
Salesfusion - Salesfusion provides an easy to use marketing automation platform that allows sales and marketing teams to be successful.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.