Like any tool, Slack is a learned skill. DeLanghe says Slack has employees who start without prior experience of the software, or who are used to using desk phones. And while much of the company's informal policies and tricks are covered during the onboarding process, she always recommends having a safeguard as well.
"Have somebody who you trust, who can help you, who already understands it," she said. "So if you feel nervous posting to a public channel, you can have a buddy and get social proof [beforehand]." (Source)