Skype for Slack - Move your slack discussions to a group skype call
Promoter - The Most Effective Way To Engage And Learn From Customers
Calls on Slack - Make voice calls in Slack
Open Loyalty for Startups - Open source stack for building customer focused products
Pingly - Your communication hub — Email, text & voice in one app
HelpCrunch - HelpCrunch Live Chat: Turn prospects into customers, drive sales and improve retention with a rich toolbox combining modern live chat, in-app messenger, email marketing, CRM and marketing automation.