Salesforce Communities is the only community platform that combines the power of social networking with business processes for breakthrough collaboration and productivity.

In Salesforce Communities,

1. We can integrate Knowledgebase, Chatter Answers, etc…
2. We can easily collaborate with Partners, Leads, Customers, etc…
3. We can share dashboards with customers.
4. For internal users, no need of separate username and password(SSO).
5. Maximum customization(design using Site.com is also supported) is allowed.
6. We can use Chatter.
7. We can promote social collaboration for sales, service and marketing business processes.