When day turns to night, the online chatroom VroniPlag Wiki starts buzzing. At 6:00 p.m., the first users begin to appear on the screen. By around 10:00 p.m., the majority of them are online.

They're looking for plagiarized work in doctoral theses. They do this all through the night, after their day jobs in many cases, but they don't get paid for it.

The number of active users on the Internet platform fluctuates. Sometimes there are half a dozen, but swarms of users crowd in to comb through dissertations written by prominent figures.

To date, the plagiarist hunters have successfully brought eight academics and politicians to account. The most famous case so far was that of the former defense minister Karl Theodor zu Guttenberg.

He plagiarized large sections of his doctoral dissertation without referencing his sources. When the issue came to light in early 2011, Guttenberg was forced to resign and was stripped of his PhD title.

More heads likely to roll

Now the plagiarist hunters have Germany's education minister, Annette Schavan, in their sights. They've found referencing mistakes and claim that around 10 percent are inconsistent.

VroniPlag activists argue that these are too "negligible" to justify the storm that has erupted around the minister. The general consensus was that their investigation into Schavan's doctoral thesis should be laid to rest.

But not everyone agrees. One VroniPlag activist defied his colleagues by publishing the results of his research on his own blog, called Schavanplag. He didn't want the issue "swept under the carpet," he said in an interview with Spiegel Online.

In addition to VroniPlag Wiki, there are other blogs and platforms where the doctoral theses of prominent figures are placed under the microscope.

They even offer charts providing a detailed overview of the unearthed irregularities. The plagiarist hunters call these charts "barcodes," marking each page of the work where errors have been found. Red and black bars stand for plagiarism, white indicates a clean sheet.

Schavan's "barcode" is almost completely white with just a few red and black bars. However: "As a model it shows that [Schavan] often cites primary sources, while actually presenting a slightly modified, near exact copy of the secondary literature," said an anonymous blogger on SchavanPlag.

Willful intent or negligence?

Online debates between bloggers center on the same question, namely, how much room for maneuver is there when referencing sources? In other words, when does referencing become plagiarism?

"There's a certain gray area," said Stefan Weber, an official assessor of academic texts and a professional plagiarist hunter. He believes that the Schavan scandal could turn out to be as big as the Guttenberg affair. "By to today's standards, [Schavan's thesis] contains plagiarism. Her PhD title must be stripped."

Harsh words. After all, the work was produced 32 years ago. But in the worst case scenario, it could cost Schavan not only her PhD title but also her job.

"It is a bit unfair," Weber admitted, "but in an ethical sense, tougher standards apply here. She presents herself not only as a politician, but as an academic. I expect from her that her work is done correctly."

From card indexes to Wikipedia

It begs the question of whether or not different standards were in play 32 years ago, when academics worked with card indexes and pens. Back then, unreferenced quotes were probably more likely to slip through the net because they weren't recognized as such. "I would say the exact opposite. Back then there was no copy-and-paste."

"Actually, today it's a lot easier to work sloppily," said Gerhard Dannemann, director of the Centre for British Studies in Berlin and plagiarist hunter on VroniPlag. He studied at the same time as Schavan and has seen students banned from seminars due to cheating.

Today, students and doctoral candidates who do cheat are exposed much more quickly since their work is often published online. That's how Dannemann catches many of today's students and deals with the situation in a prophylactic, repressive manner.

Some plagiarist hunters have also had personal experience cheating. Stefan Weber came to his current job after plagiarizing half of his theology doctoral dissertation just a few years ago. Other VroniPlag users only became aware of the extent of the problem through the Guttenberg scandal.

Outrage and irritation

Despite causing outrage, the online community of plagiarist hunters can hide behind the anonymity of the Internet. Only a few users publish their real names. Going after colleagues is also frowned upon. For that reason, plagiarist hunters striving for a career in academia prefer to remain anonymous.

"It's not about us, but about the issue," is how one user with the screen name WiseWoman explained the anonymity. As long as universities fail to take measures against plagiarism, many plagiarist hunters with remain anonymous.

WiseWoman - in real life, Debora Weber-Wulff - is calling for a clearing house at universities. Stefan Weber also believes that a centralized system of control for academic works would be a practical way to combat plagiarism.

However, he doesn't think it will be easy as universities are unlikely to audit themselves of their own free will, since it could rock their foundations. "The estimated number of unreported cases is massive," Weber said. "Universities don't want to have anything to do with it."

He also sees the swarm tactics of the digital community as being a potential pitfall. Interest in plagiarism cases is only apparent when a case involving a prominent figure hits the headlines. But his desk is struggling under the weight of suspicious academic works - even without Schavan's.