Engagement and Referrals.

Engagement answers, "Do people like this and how much?".

Referrals answer, "Is this good enough to refer to other people like me?"

At an early stage company, you're still not quite sure of the best way to monetize but you cannot monetize without seeing engagement.

For an early B2B SaaS company, getting customers is more difficult than building a product. If your early users or customers are not referring the product, the limited people, time and focus you have still needs to be put into improving the product.