Slack

Puntos a favor: I owned a company that had quite a few people working for us that were overseas and communication was key. We started using slack and it greatly improved productivity, communication, and clarity. It was very simple to learn and use for everyone in the company. It is essentially a productivity social network for a business.
You can pin important announcements and topics to the top for everyone to see. Anybody can tag anybody or a group of people in the discussion. When you tag someone you know they will receive the message because they will get a notification they have been tagged. We set up multiple channels for all of the departments such as marketing, development, management etc. Having multiple channels is convenient for everyone so that they only see relevant information.
You can archive all of the channels or particular channels for your internal records. The search feature is nice if you ever need to go back to see what was said previous. Slack integrates to almost any other software as well. We had ours integrated to Dropbox and Trello. If you use any other mainstream software then there is a high likeliness that slack integrates with it.
The app for Slack works with IOS or Android. The app works flawlessly when we used it and it was very useful. I used the app almost more than I did the desktop client. Whenever someone tags you or pins something then you will get a notification on the app. You can also change app notification settings.

Puntos en contra: The only drawback I have found with Slack is the video chat feature. It may have improved since I last used this feature but it seems to have some bugs. It would drop calls or the quality would be poor. We ended up having to use Zoom or Google hangout for the video chat. However, it is convenient within the video chat you can screen share.

Comentarios: Thanks to this software, I keep connection with a network of international experts from everywhere on a passionate subject that we continue to build together, including rich conversations , sharing documents and setup workshops all around the world.

Puntos a favor: The user interface is really elegant and powerful. I particularly appreciate the 3 pane display that allows me to see which channel have updates so I can easily switch and the right pane to see content of a thread or search results without loosing my context. I also really appreciate the possibility to add our own set of icons. In our case its particularly useful since our group discuss about methods that have their own icons. The direct message module is very useful and clearly identified as separate elements so there are no risks to mix it with other conversations. Sharing documents is quite easy and the preview helps a lot when you are searching for a specific document previously uploaded. The search functionality works well and search results are clearly displayed. Last but not least, the windows application is very useful and I appreciate to have a separate application instead of a browser tab dedicate to it.

Puntos en contra: Switching from a workspace to another one is always confusing for me. Never sure about how to use it correctly without loosing an update. Seems to be a recent change, but search results are now displayed in a popup window, then you select one result and you are redirected to the thread and loose the list of results. It's quite disturbing for me and I still have to learn how to use it in a comfortable manner. I'm also puzzled by the 'All thread' view where I'm always lost. You can scroll up and down and you never know exactly where you are. Maybe it's useful for other people but for me the best views are the Channels.