[walesmd]

And making it free, at least initially, for businesses removes the requirement of having to have a conversation about it or get permission. It's the same way Dropbox gained so much traction (arguably, the first to execute this model).

You let all of the employees use something for free, come to rely on it, and then all of a sudden it's become entrenched in the workflow/culture/whatever. At that point, it's easier to just pay for the service than to switch.

See Slack.