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

Chatlio - When you have a business to run, your average instant messaging software just will not do. You need an internal presence upon which your entire team can collaborate on. Read more about Chatlio.

Trello for Slack - Organize anything with anyone, inside Slack

slalert! - Get notified in Slack when your company/keyword is mentioned

Halp - Slack-first ticketing for internal helpdesk

Talkus - Chat with your website users from Slack