Gleam allows you to create your own Facebook App then integrate it with our Viral Share action type. This means that when users use the Viral Share to share anything on Facebook, they will go via your app & see your app details (rather than Gleam).
Go to Facebook Developers (https://developers.facebook.com) > Apps > Add New App
You'll want to select Website, fill in you App Name, then select Skip Quick Start.
In order for the share to work you must then go to Settings:
Your custom app won't work if you don't turn it on. You can do this from the Status & Review section.
It is also recommended to add a 16x16 App icon, as this is what users will see in the share box.
Once you've completed the above you just need to enter your App ID in Settings > Integrations for your site.
Once you have your sharing app setup, you'll start to see the share icon appear when users try to share a Viral action type on Facebook. When users click on the name of the App, they'll get taken to the Site URL you have setup.
Once they share on their personal timeline you'll notice that the App Name is now different (in this case "Gleam Share Demo"). When users click on this they'll get taken to the URL or website that you have setup.