"According to Slack, the breach occurred during a four-day period in February."

So, more than a month since their database was breached and they did not say anything until today? Or did it take them a month to figure out whether or not the hack was real? Either way, that is pretty bad. Don't get me wrong, their new incentives are good, and their own blog post is very transparent, but... a month? And were the data from all users available to the hackers, or only the "affected" users?

It could be interesting to hear more about how the hack took place and what changes have been made to the infrastructure, both from the perspective of a user and a fellow developer. Security by obscurity has never been a good idea.

Also, and this is more in general when reading about hacked systems; I do not care about the passwords being "computationally infeasible" to be generated. That is irrelevant. A system was hacked, data was (most likely) stolen. Period. One shouldn't really reuse passwords across services anyway.