Lawmakers are used to unannounced visits from activists on Capitol Hill and the campaign trail, but now demonstrators are following them to Facebook.

As more politicians join social networks, advocacy groups are using the sites to publicly corner officials on issues they might otherwise avoid.

The tactic is appealing because it's easy to implement, but that may be the very reason why it won't be effective in the long run. It also comes with a set of risks quite separate from real-world activism.

It's an easy tactic that a handful of activists can implement. Most politicians leave their Facebook walls open for anyone to post comments, giving constituents a way to communicate with lawmakers.

Activists exploit that by repeatedly posting the same message, perhaps a request to sponsor a bill, until the lawmaker's entire wall is completely covered. That pressures lawmakers to acknowledge the request and respond.

Last month, Rep. John Boozman, an Arkansas Republican, agreed to cosponsor a bill (HR 4128 ) about minerals from Congo after receiving more than 1,200 Facebook comments from activists led by the liberal Center for American Progress.

Boozman demonstrated his social media prowess by doing so on Twitter .

"We encourage it. We learn a lot from those interactions," the lawmaker said of social media.

Lawmakers treat Facebook posts differently than letters. Boozman said that he welcomes interactions from his constituents through all mediums. But when someone takes the time to write a personalized note or visit his office, he pays more attention.

"That shows they truly are committed to the issue," he said.

Because people can write Facebook posts so easily and often, the tactic can also overwhelm congressional staff and make it harder for them to track individual posts.

"When we go through periods like with health care and other issues that so many people want to weigh in on, it becomes difficult," he said. "The sheer numbers can be overwhelming."

That campaign worked because so few people are posting so far. Like many lawmakers, Boozman's wall is static enough that the advocacy posts lingered there and stood out.

"We're definitely in a space where these things are kind of new," said Fred Stutzman , a doctoral student studying social networks at the University of North Carolina in Chapel Hill.

Stutzman doesn't expect this moment to last. He argued that lawmakers may eventually censor their social networking pages or move to sites that allow them more control over what people can post.

"Politicians like any other individual or corporation are very concerned about their brand," he said.

Activists may also crowd each other out as more of them start using social networking to reach lawmakers.

A group of D.C. activists recently tried the same tactic to pressure mayoral candidates to restructure the district's taxes. They got noticed with just 150 posts .

That won't be possible when thousands of other groups target the same politicians at the same time. The group's posts would simply get lost in the shuffle.

"It may be effective in the short term, but it will not be effective in the long term. This is the classic problem with political messaging right now. It's become so easy to do things like this," said social media commentator Clay Shirky , author of "Here Comes Everybody: The Power of Organizing Without Organizations."

The tactic works best when constituents are involved. Online technologies make it easier for lawmakers to have a national, even international audience, but they still rely on their constituents for votes.

The advocacy campaigns that will be most successful are those that have constituents write on their lawmakers' walls.

Other campaigns, Shirky said, "will wane in effectiveness as congressional staff come to understand how little those protests say about what the constituents are actually feeling."

Facebook sit-ins will also work best in tandem with other protest techniques, especially in-person meetings and protests. Staffers keep an eye out for issues that have a growing following of activists, and they are more likely to pay attention to a Facebook campaign if it reflects concerns they have heard elsewhere.

Online campaigns come with their own risks. The public nature of Facebook is what makes this tactic unique and effective, but it also carries a risk for the activists who take part.

When they write on the lawmakers' walls, they make their political position visible to everyone from prospective employers to friends. In the past, activists who attend rallies with thousands of people have enjoyed a sort of anonymity that the Internet eliminates.

Twitter's recent announcement that the Library of Congress will be archiving all of its content shows how such statements can be preserved for long after an activist has made them.

President Obama is just one of many prominent individuals who have warned young activists about the perils of this.

"Be careful what you post on Facebook," he said to high school students in Virginia last fall . "Whatever you do, it will be pulled up later in your life."

Ambreen Ali writes for Congress.org.

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