Talkus - Chat with your website users from Slack

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

Halp - Slack-first ticketing for internal helpdesk

Slaask for Social Networks - Chat with your customers on Facebook and Twitter via Slack!