A Custom Domain is a unique branded name that helps you identify a website. It's a way for you to increase brand recognition by allowing viewers to quickly associate your links to your product/company.
Adding a Custom Domain to your Bitly account replaces the "bit.ly" domain, with your own custom one, when you create links.
A standard link created with Bitly would resemble something like bit.ly/abc123. If however, you were to add a custom domain, let's use ESPN's in this example, the link would resemble something like es.pn/abc123.
Custom Domains drive more than just brand impressions and visibility – they can drive up to a 34% increase in CTR. Learn more about the value of Branded Short Domains in this case study.