When creating an Action Page or a Smart Link, you can now include an easy subscribe button that will grow your YouTube subscribe and leave you with the fan email in your link analytics / audience tab.
On an Action Page
first step - add the YouTube Subscribe as an action on the page:
second step enter in the fields:
Channel URL - the YouTube channel you want fans to subscribe to
Include a post action destination URL - you can have fans redirected to any page after a successful subscribe action
On a Smart Link
in the Link Creation tab, you can search for YouTube Subscribe action from the list of supported services, and then click "Add Store" button
then you can set the YouTube channel in the "Link" field
and save your SmartLink.