spotplex12.jpgThe web offers more than a few sites with variations on the Digg theme, but Spotplex, which has designed a potentially more democratic ranking system, is different.

Instead of the submit-and-vote system used by Digg and its clones, Spotplex ranks articles based on the number of impressions they get. Bloggers insert a line of code into their blogs, and Spotplex works in the background, tallying each time someone lands on an article’s page.

Spotplex, of Santa Clara, Calif., officially launches tomorrow.

The results of these tallies show up in real time on Spotplex’s page, which is mostly just like Digg’s. You can see the total number of times an article has been read, browse by categories like technology, politics, and entertainment, and change the time-frame of rankings from the last 24 hours to the last hour, month, and all time. In a useful touch, you can toggle between “relative” and “absolute” popularity. “Relative” popularity weights views against a blog’s overall traffic, so sites that don’t have a massive readership but have an unusually popular article have a chance to show up on the front page.

Spotplex’s chief executive Doyon Kim argues his company’s method is a more legitimate way to determine the popularity of a post. Spotplex is not overrun by the the tech-savvy elite that dominate Digg. In theory, he may be right.

Spotplex requires no active user behavior, like Digging or tagging, and readers don’t have to sign up for anything. It cannot be gamed in the same way that Digg can, and is immune to the user rebellions that have been an occasional headache for the massively popular aggregator.

That is not to say that Spotplex cannot be gamed. Digg, while facing corruption at the hands of services like Subvert and Profit (see TechCrunch coverage here) at least requires humans to submit and vote on articles. Spotplex’s automated system could be more vulnerable to cleverly designed bots. Further, because it only measures impressions on individual article’s pages, it misses traffic from people who read blog entries through a feed reader or simply on the blog’s main page.

But the more significant problem is that unless it succeeds at gaining mass adoption, Spotplex will not be relevant. With Digg, despite its heavily-skewed male techie demographic, blogs from anywhere on the web at least have a chance to gain recognition. With Spotplex, if you haven’t signed up your blog, you’re off the grid.

Spotplex hopes to entice bloggers by offering a widget that will list a blog’s most popular posts in the sidebar — possibly driving more pageviews — but it has a very long way to go. Moreover, once the concept is out there, there’s nothing stopping widespread and entrenched widgets like MyBlogLog from throwing together some code and producing a similar offering. To succeed, it will need to stay one step ahead of hackers, gain momentum and start driving noticeable traffic to participating blogs.

Meanwhile, Digg has reportedly blazed by the 20 million unique visitors mark (the figure is disputed) .