Oct 29, 2010 13:52 GMT  ·  By

YouTube is marking pretty big milestone. Users have now subscribed to YouTube channels and other users 1 billion times. The subscribe button, which was introduced in 2006, has proven crucial to the video site.

"Today, the [subscribe] button... hits an important landmark: it’s been clicked over one billion times. And who was the lucky channel to get that billionth hit? It was MachinimaSports, who are, not coincidentally, on our homepage on Friday," YouTube announced.

"In fact, there is so much subscription activity that there are over a billion subscription notification emails sent every week," it added.

The subscribe button has been very important for YouTube for one thing, building an audience.

At first, the site grew fast thanks to hit-and-run visits, random videos posted on blogs, or videos users found through the search feature, but subscriptions provide a much more reliable and steady source of activity on the site.

They also enables users to visit the site and find great content without having to figure out what they want to watch next. If they liked something from a channel at one point, they'll likely like other videos from the same source.

For video creators, it's a very important tool as it enables them to create a community around their videos and enables them to hold on to and communicate with their fans a lot easier.

For YouTube, though, it means more activity, more videos watched, more people visiting and more ads served. What's more, channels with a lot of subscribers generally dish out higher quality content making advertisers more comfortable with running ads next to them.

To celebrate the event, YouTube is launching a rather interesting new feature, embeddable subscribe buttons. Now, even if most of your YouTube videos are watched on your blog or website, you can ensure that the fans don't miss any of them by embedding the YouTube Subscribe button.