Once you know what elements you need to concentrate on, you can come up with an estimate for the ROI that you expect to see from the community. Some elements to focus on could be:

• Ticket deflection: What's your cost to handle a ticket? This will vary depending on the complexity of both your product and the case in hand, but is often somewhere between $1- and $100
• New leads: Consider your community as a marketing asset to help prospects, to upsell and to cross sell. Include the added SEO value provided by your community forum
• Lead conversion rate: Your community can be a place where your prospects validate their decision to buy your products. They can see what kind of community support is available to them, and how much other customers are enjoying your product. Community allows for a strong secondary benefit to a purchase. Not just your product, but the community that comes along with it.
• Reducing churn: Every business needs repeat custom, so give your users a reason to stay with your product. When customers have strong bonds in the community, they aren't just leaving your product. They're leaving a social group, and the relationships they've built there.
• Customer Advocacy: Brand advocates are a powerful force in marketing, and the best way to recruit them is a strong community. Getting these heavy-hitting customers in your corner is a way to ensure that everyone they know will hear about your products, without a penny of extra spending from you.