Drupal is designed to be a multi-user content management system/framework. This means you can have people sign up and create user accounts and assign roles to them. You can make these roles have specific permissions. For Drupal Commerce, you could create a product type called "Community Products" and a node with a product reference field called "Community Products Display" and then assign "Create, Edit, View their own Community Products" to your newly created role. Also give them access to "Create, Edit, View their own Community Products Display". Now the trick will be to make sure they know enough about adding products and referencing them on the node page for display to make it work.

* User Module Documentation - http://drupal.org/documentation/modules/user
* Explanation of roles and how permissions work - http://drupal.org/node/22275

Hope that helps :)

Josh