Custom sources allow you to add review sources to your Digitalift account for sites that we don't support. This is useful in several regards:
Manually add reviews from those sites to the system
Show those reviews off through our widgets
Generate reviews on that custom source from our landing page
Get your custom source added by visiting Reviews and then Custom Sources in your Digitalift dashboard. Once that's added, it'll show up alongside all our supported review sources in the Review Sources dashboard.