1. Create a new app at the following URL: https://developers.facebook.com/apps (note: Create new app button is located in the top right corner of this page) Choose Advanced setup.
2. Name your app (example: 'Your Store Product Comments'), leave the other fields empty and click Continue.
3. On the application settings page, click "Add platform" button and then click "website" icon.
4. Enter your Starter Site URL in Site URL and Mobile Site URL fields.
5. Write down your APP ID and save it.
6. Please note, there is no necessity to make this app available to the general public. This application works properly in the development mode.
7. Go to the Ecwid control panel, click Settings - > Social Tools -> FB Comments
8. Click Enable next to Show FB Comments and include the app id you entered in Step 5.
9. Click Save
10. You can now moderate your comments here: http://developers.facebook.com/tools/comments
Screenshot (an example of app settings):