In order to promote channel subscriptions (and to make it easier for channel owners to gain more subscribers), YouTube has just launched a subscribe button that's embeddable on any site on the web.
"The YouTube Subscribe Button lets you add a one-click Subscribe button to any page. The button lets people subscribe to your YouTube channel without having to leave your site to either log in to YouTube or confirm their subscriptions," says YouTube on their developers page.
YouTube nows offers 6 different button formats - three for free channels and three for their new paid channels (which may be off to a slow start). When people click on the subscribe button on your site, it'll automatically subscribe them to the specific channel. This is a bit different for paid channels, where clicking on the subscribe button will take the user to the channel on YouTube, where they can choose whether or not they want to pay to subscribe there.
Here are the 6 button options:
The new subscribe button is easily embeddable on any site, and YouTube only has a few rules concerning what channel owners can't do with the button. First, they can't offer rewards in exchange for subscribing to a YouTube channel. Second, the buttons must be "fully and clearly visible." And lastly:
You may not use a Subscribe Button to track any data about a user related to the user's actions or browsing activity, including without limitation whether or not a user clicks on a YouTube Subscribe button. This prohibition includes but is not limited to using pixels, cookies, or other methods of recognizing when a user clicks on a YouTube button.
For more info on how to add a YouTube subscribe button to your site, check here.