When Time magazine named the protester as the person of the year, the images that immediately come to mind are of the masses in Tahrir Square or rain-soaked tents and police raids of Zuccotti Park. What didn't get as much attention was the behind-the scenes work of online activists stationed in bedrooms and offices across the country that made 2011 a particularly worrisome year for any government official or corporation that found itself in the crosshairs of a protest.

A new breed of Web-savvy rabble rousers has discovered how to leverage the crushing power of online outcry against companies such as JCPenney, Pepsi, and Lowe's—without ever having to set up a tent in a park.

This wave of Internet activists are starting campaigns on Twitter, targeting ads on Facebook, and creating petitions that skyrocket to thousands of signatures in just hours. It's something that can catch a company by surprise if you don't know where to look for it.

Would-be mischief-makers got a crash course in trouble making at last month's Netroots conference at Pace University in New York City. In addition to panels on the impact of Occupy Wall Street and the future of local blogging, the conference featured several panels on how activists can use online tools: one was called "How to Scare Companies and Influence People Online," another was "Twitter: Advanced Strategy and Mischief."

"Increasingly, the ways in which companies are thinking about their customers and reaching out to their customer base has to do with the online world," said Asher Huey, a democratic consultant and strategist. "Through social media and the online world, there are all these different channels for getting to corporations."

Huey found this out when he wanted to combat what he saw as Donald Trump's racism toward President Obama. He started a Twitter account, @DumpDtrump, which grew to 4,400 followers within a few weeks. Plenty of the followers served as an echo chamber for the message that companies should stop advertising on Trump's show, The Apprentice. Soon after, Groupon pulled its ads that would have run during the show—and other companies followed.

Huey then took aim at another advertiser that bought airtime during The Apprentice: Pepsi. He did so by posting on the company's Facebook wall. But then he upped the ante, buying ads specifically targeted at Pepsi employees, asking "Why is Pepsi ignoring its customers?" and "how does it feel to work for a company that sponsors racism?"'

"That's going directly after their brand," he said.

No research has yet been conducted showing how effective online protests are compared to on-the-ground campaigns, says Jennifer Earl, a professor of sociology at the Univeristy of California Santa Barbara and co-author of the 2011 book Digitally Enabled Social Change: Activism in the Internet Age (Acting with Technology). But as the transaction costs continue to shrink, companies should expect the wave of pesky protesters to grow exponentially.

"The costs of organizing a campaign or participating in a campaign can be so low online, if you organize the campaign right," she says. People who otherwise would  complain privately "now have a medium to pursue those grievances."

"There are lots of ways people can target corporations using the Internet," Earl said.

Bob Garfield, host of NPR's On the Media, told WNYC's Brian Lehrer on Tuesday that companies that don't pay attention to this risk being steamrolled by public protest.

"In the old days, it was hard to organize a consumer boycott," he said. "But In a connected world, assuming someone has acted very egregiously, you can very quickly form a mob to go into the street, and you can very quickly form a mob not to go into a chain of stores." 

Where Does Hacktivism Start? Research.

In general, this breed of online mischief starts, like everything these days, with Google. Elizabeth Jenkins, new media coordinator for an affiliate of the Service Employees International Union, told the conference crowd that research is the foundation of online activism—and there's more company information online than most people think.

The search engine Pipl.com contains information about common aliases, screen names and online personas, a tool useful for helping ferret out so-called Astroturf—or fake grassroots campaigns by companies—she said. Some activists sift through Slideshare for bits of info in the presentations companies upload. Google doesn't index the individual pages, but a savvy user can find the right kind of company presentation; including, Jenkins said, occasional financial data and other private company tidbits.

Even common sites like LinkedIn are useful because they can help activists learn how they are connected to the targets at the companies. 

Learn the Tools of the Trade.

There's overt protest, which is easy to spot, and then there's the more subversive tactics to watch out for. Jenkins cited a campaign aimed at DKNY's fur line where PETA posted a stream of messages on the company's Facebook wall; but PETA changed its profile image to a different letter each time so the messages read "BUNNY BUTCHER" in a vertical line.

"They're also listening. They're keeping an ear out for protecting their brand," Huey says. "If you mention them on your Facebook wall, chances are they're paying attention."

Petitions have gained new clout too, when done properly. Once the milieu of door-knocking zealots, and then disregarded as e-mail chain letter spam, new services such as Act.ly and Change.org have mixed the finesse of social networks with the critical mass of an Occupy movement. One of the most public instances was a campaign against a JCPenney shirt some considered sexist and condescending to girls. Each of the 1,600 digital signatures collected in a matter of hours sent an e-mail to company headquarters. The shirt was quickly pulled, and the company apologized.

"Even with a small target, getting even 50 e-mails to someone can have a really big impact," Jenkins said.

Even without the tools, Twitter is being used to amplify a message just as a bullhorn on the sidewalk in front of an office might have done years ago. Beth Becker, co-founder of Progressive PST, a social media consulting company that works with campaigns, legislative offices, unions, and non-profits, told the conference that activists need to be aware not just of how to use the service, but also how to stay engaged. There's ample chance for mischief, especially since Twitter allows you to create up to five accounts in one day from one IP address, she said.

"There's a lot of Astroturf on social media in general, especially on Twitter," she said.

The service is even experimenting with being able to target messages to specific lists of people, something activists think could help their cause by decreasing the clutter online, she said.

Activists have learned tricks like the "bank shot" to get the most out of Twitter, a sort of back door way to spread a message virally. For example, Becker wanted to get a news item in front of TV host Keith Olbermann, but knew he would never see it among his 350,000 followers. Instead, they targeted the message at someone Olbermann follows, who then retweeted it, getting the message in front of the host, who ended up covering the topic on his show.

"It's not about how many followers you have, its about how many followers they have," she said. "It's never about the immediate audience. It's about the network."