When protesters in Egypt overturned the country's government, Twitter got some of the credit.

But Danny O'Brian of the nonprofit Committee to Project Journalists pointed out at the South by Southwest festival yesterday that social networking sites can be a curse to activists, too. "We see the social tools being used by activists or independent journalists becoming a lever to be used against them, to monitor them, to implicate them, or reveal their sources," he said, suggesting that social networking sites be tuned to prevent that and protect political activists in oppressive regimes.

Examples of web services flipping from enabler to disabler include the way Yahoo's Chinese webmail servers were used by the government to identify and then jail political activists. More recently, prominent Chinese blogger and free speech advocate Michael Anti lost a network of 1000 contacts he had built up on Facebook after someone (assumed to be politically motivated) reported him for a technical breach of the site's terms of service.

He was reported for not using his real name, although he has lived for decades and attended Harvard University as Michael Anti. Social sites can't make exceptions to the terms of service (ToS) they ask users to abide by, said Jillian York, of the Berkman Center for Internet & Society, but Facebook should consider adding nuance to its strict name requirements.

When a person is found to have breached Facebook's ToS their account disappears along with their photos, contacts, and other content. That process can be triggered when one user complains about another, creating a tool that can be used to quash free speech, said York. Government agents and competing activist groups report their enemies to pitch their accounts into lock down and their owners into a lengthy, unwieldy claims process. One example was an Arabic group who used the tactic to close down atheist activists on Facebook.

"[Facebook's policy] skews against people who are famous and have enemies," said York, "I believe you should get a choice of what name you use."

Photo-sharing site Flickr, which has no qualms about users taking any name they please, doesn't have such problems, said Ebele Okobi-Harris, director of Yahoo's business and human rights program. "Unlike Facebook's real-name policy our policies can't actually put users at risk," she said, while the company runs every pending product release past her team to screen out potential risks to human rights.

Flickr is under fire from human rights advocates nonetheless this week, for taking down photos uploaded by Egyptian photographer and activist Hossam el-Hamalawy showing alleged members of Egypt's secret police. Flickr took them down after other users reported them for copyright infringement. El-Hamalawy had uploaded a photo taken by someone else, breaching the sites ToS.

Flickr, Facebook and other social sites may not want to politicize themselves by making exceptions or design tweaks to make room for activists. But they can't ignore the problem and hope it goes away.

"I can't truly recommend that anyone use these services for activism in oppressive places," said O'Brian, "but on the other hand, how can you not use Facebook?" As social tools become more powerful and widely used, incidents like Anti's will likely become more common; activists have nowhere else to go online that offers the same features. Some firms, such as Twitter, have actively tweaked their services to help ongoing protest movements like that in the Middle East. Perhaps in the end the commercial imperative to avoid bad publicity will make others take a similar course for business, not political reasons.

Sometimes, an idea sweeps Twitter, touching the conversation of millions of people. Many other times, ideas disappear almost as soon as they appear. Researchers at the social computing lab at HP Labs in Palo Alto and Stanford University recently wrote a paper analyzing what makes gives a topic on Twitter lasting popularity.

Twitter tracks these subjects of conversation in a "trending topics" list, and the researchers collected this data every 20 minutes for 40 days. They also collected tweets mentioning these topics every 20 minutes. They put the data together and studied it to draw conclusions about what makes a topic last.

Most trending topics disappear again fairly quickly, the researchers found, fizzling out within 20 to 40 minutes. Some, however, last for days.

The researchers write:

When we considered the impact of the users of the network, we discovered that the number of followers and tweet-rate of users are not the attributes that cause trends. What proves to be more important in determining trends is the retweets by other users, which is more related to the content that is being shared than the attributes of the users.

There are some people whose comments are so influential that they can launch trends almost single-handedly, but the researchers found that these topics actually tended to burn out quickly. Really, the most lasting topics were those that engaged a lot of different people, including comments from a large number of authors. In many of these cases, people were commenting on news items being discussed in traditional media.

According to the researchers:

This illustrates that social media, far from being an alternate source of news, functions more as a filter and an amplifier for interesting news from traditional media.

Twitter founder Evan Williams announced a new platform for the popular microblogging service during a keynote interview today at South By Southwest Interactive (SXSWi). The new platform, called @Anywhere, allows websites to integrate Twitter more deeply.

The platform is launching with a number of media partners, including The New York Times, Digg, The Huffington Post, and Bing. Williams said it will allow users to, for example, discover and follow a writer's Twitter account simply by hovering over a byline in a news article, or to follow a band after finding its name in the text of an article.

The idea of the platform, Williams said, is to reduce the friction that prevents more engagement. If the platform is adopted, he said, it "should result in more followers for a site," as well as more community interaction. He referred to the platform as an "@" platform rather than an "app" platform.

Williams was thin on details, despite some prodding during the keynote interview. In some respects, this seemed to be because the platform is designed to be flexible and he's not yet sure how sites will use it. I did, however, wish that he would use more than 140 characters to describe how it was intended to be used.