Slack

Slack is an online messaging platform for teams, with apps available for a number of different devices. Shown here is the Web app. The interface puts messages front and center and reserves the left side for a menu bar, with a few additional options along the top.

Slack has apps for a variety of operating systems and platforms, including iPhone (shown here).

Slack lets you have group conversations that are public and searchable, as well as private conversations between you and one other person, you and several others, or you and the Slackbot.

Slack's notification options are one of the reasons it's such a useful team communication app. You can easily set the app with a recurring Do Not Disturb Mode, so that you can sleep in peace or not get involved in conversations when you don't want to.

Profiles in Slack help you get quick info on people in your team, such as phone number, time zone, and Skype ID. Slack also now has a built-in voice calling feature, so you can use Slack to get in touch in real time with audio, too.

The sidebar in Slack comes in handy if you have more than one Slack group to which you belong. The sidebar lets you easily switch between them.

Slack has more options and preferences, such as the ability to customize notification sounds.

Slack lets you change the color scheme of the interface, which is helpful for quickly differentiating between two or more Slack groups.

Slack keeps track of the number of messages sent to public groups, private groups, and as direct messages.

Slack has more statistics, too, such as graphs showing when users are more active and whether people are reading the content that's posted. Some of these stats are restricted to paying members.