Sitecore Publishing Service is the new sitecore 8.2’s publisher. It’s more efficient and comes with it’s own publishing dashboard.
More information can be found in:
There are times however that you might want to go back to the classic publishing service. Here’s the step by step instruction on how to do this:
1. Locate /sitecore/system/Aliases/Applications/Publish in CORE database and rename it to something else.
2. Rename Sitecore.Publishing.Service.config to Sitecore.Publishing.Service.disabled.
3. Rename Sitecore.Publishing.Service.Delivery.config to Sitecore.Publishing.Service.Delivery.config.disabled.