Slack offers a powerful and flexible group-messaging service that lets teams chat, host calls, and share files across platforms.
Communicate with your team: Slack is a shared communication area where you can organize and keep track of conversations, create public and private channels for specific topics or teams, and direct message colleagues. You can pin items in a channel, share files, and set a retention policy for messages.
Notifications: You can set channel notifications, so you can be alerted to new messages, just those mentioning you, or using a keyword you've designated. You can mute a channel, ignore general @channel messages, or have different notification settings for desktop and mobile. You can also format your messages -- using basic text and paragraph styles, including code blocks -- and add emoji. And finally, you can disable notifications automatically, so you don't get alerts in the middle of the night.
When text isn't enough: You can make voice and video calls to teammates right in Slack. Select a channel or person, and click the "Start a call" phone icon. In addition to voice or video chat, you can share your screen from the call. With a free account, you can make one-to-ones. With a paid account, you can include 15 people on a call.
Searchable: Slack indexes every discussion and document, so you can easily search for discussions for Microsoft Word or Google Docs files, for example.
Add apps: If Slack doesn't do something you need, you can add third-party apps into your workspace. Apps range from those for calendaring and list-keeping to making digital payments and adding GIFs to messages.
Slackbot: The Slackbot assistant alerts you when you're mentioned in a channel, can help remind you of events, and answer simple questions about how Slack works, such as how to invite people to a channel.
Broad availability: Along with its web app, Slack has apps for Mac, Windows, Linux, iOS, Android, and Windows Phone platforms.
A bit pricey: Slack has a free version designed for small teams. But for a larger enterprise setting, you are looking at $80 to $150 per person per year to take advantage of everything Slack offers. Hipchat from Atlassian, for example, is less than half that cost per user.
Slack's team-collaboration service offers just about everything you'd want in group messaging, from public and private channels and notifications to voice and video chat. Slack makes it almost effortless to collaborate with colleagues, but you pay for its ease of use.