I have created a new Slack Channel called SharePointTalk!
The purpose of this channel to allow you to have a resource for getting and sharing information on SharePoint.
I am a frequent attendee of the SharePoint Power Hour sessions hosted by Laura Rogers. She has been leveraging Slack for a while now and it has been very effective in allowing discussions between the audience and her team in real time. On occasion, people will post a question at random times and someone will answer. I think this is great way to leverage Slack!
So why would someone use Slack versus just leveraging a community like BlackExchange or Macroloft Community, or Blammer? (the names have been obfuscated to protect identities) It's a matter of very subtle differences in how communications are implemented. Regarding the depth of knowledge available on these platforms, they all have a great depth of resources from the shear number of people that access the respective sites. With some, it is much more targeted as you have to subscribe to a group - just like Slack.
So how is Slack different than <insert your collab tool here>? There are so many similarities that one could go into an endless loop in an discussion with a <insert your collab tool here> advocate. Again it falls to how the communications are implemented. For me, I like how Slack manages the groups and messages within the groups. I like how the communications are persistent and how it manages new and old messages.
My hope is that this group will be large enough to have your questions answered, but small enough that you feel you actually have a rapport with others in this group.