StumbleUpon has already been a tremendous source of web traffic for some sites. Sources have already indicated that it’s a bigger traffic driver than Facebook in the U.S. We’ve certainly seen the benefits ourselves. With new features, the potential to get traffic is even greater.

Is StumbleUpon a significant source of traffic to your site? Let us know in the comments.

StumbleUpon has been redesigned. We had a phone conversation with CEO Garrett Camp, VP, Marketing Marc Leibowtz and Director of Communications Mike Mayzel, and the company tells us they consider the relaunch “the most significant and consumer-driven product announcement to date.”

Indeed, it has the potential to make the general StumbleUpon experience more relevant to users, while greatly increasing traffic to websites.

While the relaunch comes with a redesigned homepage, toolbar and even logo (the social button has yet to be updated at this point), it’s really all about two features. One feature, you may already be familiar with – the Explore Box. It’s been in beta for months, but with the relaunch, it’s not any longer, and will appear in the upper right-hand corner anytime someone is stumbling.

We wrote about the feature back in July. I said back then that it could be viewed as “a new way to search the web,” as it lets you stumble through content based on the keywords that you enter into the search box.

Camp tells us, however, “it’s not a full-on search engine,” noting that it has expanded StumbleUpon’s discovery engine from 500 topics to half a million interests. But it’s “not a search engine for everything.”

The second feature is the one you’ll probably more interested in, however. At least a business or a website owner.

That would be channels. Sites, celebrities, brands and businesses can set up their own profiles and get people to follow them on StumbleUpon. You know, like Facebook, Twitter, LinkedIn, Google+, etc.

Before, sites always had to worry about flooding the StumbleUponiverse (call it what you want) with too much content, and driving users away, or getting content out there at the right time, but this eliminates these worries. In fact, StumbleUpon is essentially encouraging sites to share everything they have by connecting their RSS feeds or Twitter accounts to their channels.

It’s still interwoven with StumbleUpon’s algorithms. Users who follow your channel will see more of your content in the mix as they’re stumbling like usual. StumbleUpon will also recommend your content to users who like similar sites. The company tells us they’ll be implementing more channel recommendation features over time. It won’t just be a one time thing at sign up.

The feature launched with 250 channel partners. Any brand can set up a channel, and once it’s approved by StumbleUpon, the brand’s channel will be live. Here’s what a couple of the launch partners had to say about the channels.

“We’re big believers in ‘discovery’ as the dominant way that people now find content, and we’re excited to be sharing our favorite technology and innovations with the StumbleUpon universe, which is one of biggest ways to discover on the Web today,” said Linda Boff, executive director, global digital marketing, GE.

“We are focused on building an Audi community in the places where our fans interact and share with one another,” says Audi of America Chief Marketing Officer Scott Keogh. “The prospect of someone literally Stumbling onto an Audi image, video, or news story that resonates on a personal level is truly remarkable. We love to see lifelong fans or even casual Audi enthusiasts expressing their natural passion for the brand in the spaces where they connect and share lives with one another.”

I don’t know about you, but I do a fair amount of my stumbling from my phone. This graph from Fast Company shows that mobile stumbling is indeed on the rise (which should also help your traffic – be sure to have mobile-friendly content):

The mobile apps will get access to the content that comes from the channels right away, but you won’t be able to manage your channels from the mobile apps at first, though from the sound of it, this will probably come in the future.

On the site, StumbleUpon users will be able to toggle between the new and old versions over the coming weeks.

Do you intend to promote a branded StumbleUpon channel? Thoughts about the redesign in general? Let us know in the comments.