Bill Macaitis knows a little bit about growth. In his time as Zendesk CMO, he helped take the company from venture-funded startup through an IPO resulting in a $1.7 billion market cap. When he led online marketing and operations at Salesforce, he helped grow revenues from $900M to $3 billion. Today he serves as CMO at Slack, the hyper-growth messaging startup that is less than two years old and already worth north of $2B with over 500,000 users.