Easy points for when someone asks you how a community offers monetary value.
1. Advertising - GoogleAds helps you here
2. Commissions - Sales of affiliate brand products or event tickets can be a source of income
3. Market Research - A community is a specific target audience, perfect to conduct a brand's market research
4. Customer Retention & Support Costs - A commonly used method by brands. A community indirectly increases value and lifetime of a customer and reduces customer support costs.