To build your YouTube audience from all of your web properties, you can now embed the YouTube subscribe button on your site. This lets your fans subscribe with a single click without leaving your site. Once fans subscribe, they can see your channel on their YouTube homepage, phone, tablet, Playstation 3, smart TVs and millions of other devices.
Here’s what the subscribe button looks like on Vice.com
in the bottom-right corner of this screenshot:
To put the subscribe button on your site, just embed the code below like you’d embed a YouTube video.
Check out this documentation if you want to customize the button or dive into the details.