Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
UXProof - Gather experts’ feedback on your design prototype
Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors
Basil Chat - Design feedback via chat
GoSquared Live Chat - Beautiful, simple, and free live chat for your website
Presentator - Design feedback. Simplified.