Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Pluot Communications - Big-screen video conferencing for startups

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

Closer - Digitize your sales team | Video calls for sales

JivoChat - JivoChat is a live chat that enables you to talk to visitors on your website

Callpage - Turn website visitors into sales calls. Use CallPage and provide immediate free phone callback to your leads in 28 seconds.