1. Customers can answer one another's questions, thus reducing your support costs.
2. If you or a customer answers someone's question — especially with a detailed response — this information can be referenced in the future, so you don't have to recreate it every time someone sends you the same question.
3. As customers discuss your offerings, they are generating, for free, fresh content that is rich in keywords and is attractive to search engines.
4. By having an online community, customers are encouraged to visit your website more often, and then they tell others about it.
5. Customers will typically and freely share ideas on how you could improve your offerings, market them better, and reach new prospects.