Oh, I'm interested in the business decision behind that. For example why didn't they just buy (not acquire) the slack product. What were the reasons to host it in-house and manage it themselves.
* that Slack was for sale too
* that Dropbox wanted the app, rather than the people who made the app
(1) How Dropbox chooses to satisfy internal requirements/demand for a group chat solution
(2) Why/whether Dropbox should have acquired/acqhired the Zulip team