[graycat]

Could the fickle finger of fate easily cross their Buffet moat, i.e., could this be a short term fad that fades?

If they have something solid, that is, a much better solution for an important problem where their solution will have a significant barrier to entry, maybe Fred Wilson's "large network of engaged userrs" who have a significant switching cost, then okay. Do they?

[simonw]

I think they do. We introduced slack at my employer a few months ago and we now have nearly 400 users on there. Traffic to our core mailing lists has dropped to almost nothing, I've replaced several weekly status meetings with low traffic slack channels and most of my co-workers now consider it indispensable. It's also been crucial in helping us establish a new remote office and some other remote workers.

If it's anywhere bear as transformational for other companies, I can see it continuing to grow for a long time.