The images spread like a colorful tidal wave: pink and red equal signs flooded Facebook as the U.S. Supreme Court heard arguments on gay marriage. Millions of people changed their profile photos in a show of support — a move quickly countered by users posting plus signs as a mark of opposition.

From the Twitter-aided Arab Spring to the local Occupy movement organizing on Facebook, activists are turning to social media to broadcast their messages. With 39 percent of American adults using those networks to follow or promote political views, the Internet is a tempting soapbox.

In the digital age, rallying for a political cause sometimes means trading in the bullhorn for a computer mouse.

But amid the myriad postings, there's a swirling debate about whether such electronic chatter spurs real-world change or encourages nothing more than a surrogate for activism. It even has a name: "clicktivism."

"For a lot of people, the mere act of posting relieves that need or feeling for them to be involved. They feel like they did their part," said Heather LaMarre, an assistant professor at the University of Minnesota who studies strategic communication. "There's sort of a social expectation that somebody else is going to show up for the rally."

The latest online outcry during the gay marriage hearing was so loud that Facebook said it exemplified the way social media can illustrate support for a political and social idea. But how helpful can a tweet or status update be in effecting real change?

Get online, or go outside?

Nick Espinosa, an organizer with Occupy Homes MN, was initially drawn to the national Occupy movement after seeing posts about it on Twitter and Facebook.

Now he uses social media, text messages and e-mail blasts to summon people to attend protests at homes in foreclosure, occupying the properties to prevent banks from boarding them up. But even well deployed social media have limits.

"Online tools will never be a substitute for real on-the-ground and in-the-streets organizing," said Espinosa. "That's where change really happens."

There's no doubt that social media can amplify the message through tweets or videos. And while all the extra online attention is encouraging, activists recognize that a meme or digital petition gone viral doesn't always bring change on its own.

After the Susan G. Komen Foundation stopped giving grant money to Planned Parenthood, a barrage of negative public comments via e-mail, Twitter and Facebook, combined with pressure from politicians and other interest groups, ultimately forced the breast cancer charity to reverse its decision.

But the viral video known as Kony 2012, urging the capture of Ugandan guerrilla and war criminal Joseph Kony, raised awareness with mixed results. His name is known worldwide, but Kony is still at large.

In some ways, organizers say, digital campaigns cheapen the activism by making it so easy.

"It's not uncommon for petitions to have 10,000 or 100,000 signers," Espinosa said. "That means something very different now than it did 10 years ago."

Ryan Lyk, chairman of the Minnesota College Republicans, said the group's Facebook page has best served as a venue to excite members, distribute information and encourage action in the real world, especially visits to political representatives.

"If you really are that passionate about these issues, take it a step further," Lyk said.

The Minnesota College Republicans work hard to keep their Facebook page dynamic, posting infographics and humorous tidbits to give the more than 2,400 people who "like" it reasons to come back regularly and talk to one another.

However, old-fashioned communication — such as phones or face-to-face communication — still works better to guarantee turnout at events because, Lyk said, responding to a Facebook post doesn't always equal commitment.

"Anyone can click 'attending' " he said.

Adam Bush, 31, of Savage wasn't expecting to spur big change when he posted the red equal sign, created by the Human Rights Campaign, in place of his profile picture.

"The Supreme Court isn't going to see it, and it's not going to make any difference in the Legislature," he said.

Sending a message

Still, he wanted to send a message to gay and lesbian friends and family members who would like to marry. "It lets them know I'm fully in support," he said.

Bush was just one of the millions who changed profile pictures on the first day the Supreme Court considered gay marriage.

Such gestures, however intangible the results may seem, have been meaningful in influencing opinions on gay rights, said Jake Loesch, communications director with Minnesotans United for All Families.

"Things like this are conversation starters," he said. "The things that we choose to share on the Internet and on social media and our own profiles say something about us. We're willing to take a stand."

But LaMarre, the communications professor, cautioned that while social media are revolutionary in that they give everyone a chance to be heard, it's still unclear what change the digital chorus can bring.

"It's not a magic bullet," she said. "It's just not."

Katie Humphrey • 612-673-4758