Political groups have been caught red-handed trying to create a false sense of grassroots momentum on Twitter.

The discovery made by Indiana University's Truthy data mining tool is just the latest example of how activists are using social networks to their advantage.

Twitter is ripe for AstroTurfing because of the relative anonymity on the site. Because Twitter judges the popularity of a meme by how often it is shared with others, users can simply create multiple accounts to boost their content.

"It's very, very easy to set up simple scripts to do this," said Filippo Menczer, an associate professor on the team. The group has been interested in studying how ideas spread online.

Creating fake accounts violates Twitter's rules, but the practice helped the groups promote information—whether it be a cause, a website link or an outright lie.

"Rumors gradually acquire more credibility and appeal as we become more exposed to them," said Bruno Goncalves, a research associate on the project. "The rumor becomes so widespread that it is considered as common knowledge within a community and hence true."

One blatant example the team unearthed came from the Twitter accounts @PeaceKaren_25 and @HopeMarie_25.

Both tweeted the same 20,000 messages that included links to gopleader.gov and the Twitter handle belonging to Rep. John Boehner (R-Ohio), helping to increase the popularity of those links on Twitter and in Google searches.

"There were many people who retweeted their accounts," Menczer said.

The practice may give activists a way to promote their cause, but it comes with serious risks.

Unlike other examples of activists manipulating social networks, such as the Facebook sit-in, this one violates site rules and could undermine a group's credibility.

"In online advocacy, there is no greater sin than sock puppetry," said Jonathan Hutson, a spokesman for the Enough Project. The group advocates against genocide using social media tactics like the Facebook sit-in.

Hutson has more than 32,000 followers on Twitter, a feat he attributes to being transparent about his work and beliefs.

"When activists declare openly in their Twitter profile who they are and what their affiliations are, we build credibility for our cause," he said.

It's also pretty easy to get caught using these techniques, which mimic how spammers take advantage of Twitter. The site took down several of the accounts mentioned in the study and has invited users to flag suspicious activity.

Menczer said the Truthy tool found several other examples this week, and the accounts were already suspended by the time his team checked them out.

One network the team accused of smearing a political candidate was still live on Thursday.

The group found about 10 bot accounts such as @krossnews, @kingdomcast, and @BethlehemTweets that frequently share posts opposing Democratic Senate candidate Chris Coons of Delaware.

"To avoid detection by Twitter, duplicate tweets are cleverly disguised by adding different hashtags or subtly tweaking the web addresses," Goncalves said.

Many of the tweets link to Freedomist.com, a conservative site, that has called Truthy's data-driven work a "leftist smear." The site owners did not comment on whether the allegations were true.

So far, Truthy's examples of Twitter AstroTurfing all lean right, a fact the researchers attribute that to the popularity of conservative activism in this election cycle.

"There is just very little traffic on Twitter from the left this political season," Menczer said.

Ambreen Ali writes for Congress.org.

Like us on Facebook. Follow us on Twitter.