Slack is an instant messaging and team communication software, which was developed by Slack Technologies, Inc. and released in February 2014. The software is oriented for work and business. Slack has a freemium business model, which means you can use it for free with limited features, or else buy a paid version with the most features.
Features
Slack is available for Windows, Mac OS X, iOS, and Android, and as an app for the Apple Watch. Slack has many features, which range from simple texting to more complicated features like to-do lists and project management, video conferencing, and live chat with other teams.
Design
The design is simple, with a chat interface that can be customized.
Information about replayability of Slack
Some people say that their team has more or less the same conversation on a daily basis and that Slack is not replayable.
Conclusion
Slack is a great way to communicate with your team. It's easy to use and has some nice features. It's not a good choice if your team has not already adopted it. It's not a good idea to use Slack if you don't have much to say.