How Digg Combats Cheaters

Data-visualization tools and community policing help keep Digg's social news site legitimate and valuable to its readers.

Digg, the popular aggregation website, is redefining the way that many people find news. Some 850,000 registered users effectively act as an editorial staff, recommending--or "digging"--stories that they deem interesting enough for the site's home page.

A visual map of digging behavior on Digg. The horizontal axis represents Digg users; the newest are on the far right. The vertical axis represents stories; the newest are at the bottom. Each dot on the map represents a digg, with red dots belonging to a story’s first digg. The horizontal white lines represent digging activity for a popular story. However, the vertical white lines do not describe typical digging behavior and may represent bot activity. Credit: DIGG

The challenges are keeping undesirable content out and making sure that stories are promoted legitimately. Some people try to "game" the system, using dishonest means to try to increase a story's chance of getting to the main page. The motivation: money and fame. Articles featured on Digg's home page typically generate a lot of profitable page views for the source of the story. Gaming attempts takes place in many different ways. Some people create fake user accounts and software called bots, designed to automatically digg stories. Other gamers write fabricated interviews with famous people and post them on suspiciously new blogs in hopes of driving traffic to their website.

According to Digg's founder, Kevin Rose, the site is designed so that users can monitor digging behavior and self-police. For instance, it's possible to view the history of users who digg a story: if a story has a large number of diggs from people with newly created user accounts, it's likely to have been promoted unfairly, potentially from a single user who fabricated the accounts. Members can then use tools to "bury" stories that they don't think deserve to be on the front page.

Suspicious activity can also be thwarted using the wealth of data on normal digging behavior that Digg has gathered from past use. "With more than two years of experience and statistical and behavioral analysis into the patterns of how legitimate content is submitted and promoted--represented by over 1,200,000 content submissions and 50,000,000 Diggs to date--we have a very detailed understanding of the process," says Rose.

Finding meaningful patterns in gigabytes of raw data isn't easy. But certain data-visualization tools can  be used to detect suspicious activity easier. "By representing user activity graphically, we can start to see patterns that wouldn't be normally apparent by other means," says Eric Rodenbeck, founder of Stamen, the design firm that provides visualization tools for Digg Labs. Stamen developed Digg Labs, which includes visualization tools called Digg Stack and Digg Swarm. These tools show Digg-user behavior in real time to help users find popular stories in different ways.

"Digg Swarm is a good example of how this kind of visualization works," says Rodenbeck, who isn't a representative for Digg. "The visualization won't tell you everything about the activity that you're observing, but it can illuminate patterns that can give you a better idea of where to look."

For example, Stamen's visual map (see image above), designed by technical director Michal Migurski, offers a different perspective on digging behavior. In this image, Digg members are represented on the horizontal axis, with the newest members on the far right, the oldest on the far left. Stories are represented on the vertical axis, with the newest at the bottom, the oldest at the top. Each dot on the map represents a single digg, with red dots belonging to a story's first digg.