Traffic makes the world go round. And after getting Stumbled and Dugg this last week for the first time on this blog, social media is a great way to score big traffic numbers in mere moments. But you guys already knew all of that, right?

What I’m going to be talking about today is which social media site should you focus on. This is, by no means, a scientific study, but simply a survey of which social media site works best for individual blogs and the blogosphere as a whole.

Let’s start with StumbleUpon. It covers a huge array of subjects, so you’re bound to find one that your blog or website fits into nicely. Furthermore, if you’ve got money to burn and you want to send some new visitors your way, they offer a fairly cheap advertising program for just pennies per visitor. However, the problem with all of this stumbling is that very few people stick around. A lot of stumblers, myself included, keep their fingers on the Stumble! button just ready to hammer it the moment they lose interest. The ease of stumbling to a new site makes your bounce rate suffer.

On the other hand, we have Digg. It’s arguably better known, and has a huge user base, but lacks the massive depth of categories found on StumbleUpon. This makes it best for niches like technology, current events, and even celebrity gossip, but all but useless to make money online bloggers, photography bloggers, and other niches that don’t fit squarely into Digg’s mold. Maybe one post here or there will apply to Digg’s topic guidelines–but don’t expect every one of your great posts to.

Now that we’ve covered the sites themselves, let’s talk traffic. That’s what you’re all here for anyway, right? With StumbleUpon, you have unlimited time to get your site from no stumbles, no reviews, to tens of thousands of stumbles and many reviews. You post something, people find it, they like it, their friends find it, and so on. Traffic from StumbleUpon may start slow, but eventually it will reach a breaking point.

Digg, however, operates in a much more peculiar way. You submit a site, blog post, photo, video, whatever to Digg with a catchy headline and a quick summary that draws visitors in. They click your link, visit your site, go back to Digg and vote it up if they like it. Simple. Except you don’t get much traffic until you actually hit the Digg front page. For as long as you’re in the upcoming section, you’ll see your Diggs go up–but your traffic stays pretty much the same. For the post in question, the story ended up with 108 Diggs, but according to analytics only about 35 people actually came from Digg to read the post. That’s a whole lot of blind Digging going on.

StumbleUpon is the clear winner, though the high bounce rate is a bit disconcerting. Your stumbled posts generate traffic for weeks or months to come, there’s more niches to squeeze into than with Digg, and the system has an air of fairness to it.

Obviously, if you can get your post both Stumbled and on the Digg Front Page, you’re in a win-win situation.