Does ClerkHound support online marketplaces like Reverb?

ClerkHound DOES support integration with online marketplaces like Reverb. You can can configure and publish your products to Reverb. See the Reverb tab in Folders. When you ready you press the publish button.

When your inventory is added/removed in ClerkHound, it will automatically update in Reverb. 

When you sell a product in Reverb, an "Online" invoice is created in ClerkHound as "unshipped". When you ship the item, you mark is as shipped and it is removed from inventory.