I was looking for a Slack alternative for a while and also looking for ways to 'pin' frequently asked for links from my students. Rake is a great alternative. I am able to bookmark 5 or 6 links on my workspace that students in my channel can access. I also love that unlike the free Slack version, all my conversations are saved. Another bonus is that I am able to interact with prospects on my website. I have been able to book 2 meetings through this function already. Once they add a Windows app, it will be even better. In the meantime, their iphone app works great. Highly recommend if you need a tool that has channels and chat.