A hashtag made headlines again this week. #YesAllWomen was created in the wake of the Isla Vista shootings as a way for women to share their experiences of being threatened with male violence, particularly when they refused sexual advances. The hashtag has stayed on the list of US trending topics for several days—and led to dozens of second-day news stories and opinion pieces.

Journalists have always covered “trending” topics. But in the pre-Twitter era, the trends weren’t algorithmically ranked. As activists have clamored to create and promote hashtags to draw attention to their issues—so-called “hashtag activism”—journalists have had to figure out when a Twitter trend merits news coverage. Or, in some cases, whether the hashtag is news in and of itself. Increasingly, they decide that it is.

Slate described hashtag activism as a way “to divert public attention to new subjects.” And indeed, many of the news stories that have been subject to the efforts of hashtag activists have succeeded in redirecting the attention of both the public and reporters toward a previously more obscure angle. But while hashtag activism is a good way to introduce a story or perspective into the mainstream news cycle, it doesn’t typically lead to sustained coverage of that story.

It’s no coincidence that hashtag activism exists in “the stream”—a shorthand for the social-media experience of seeing the latest content and updates from a variety of news sources, rather than seeing an editor-curated set of headlines on each outlet’s homepage. “The Stream,” wrote Atlantic technology writer Alexis Madrigal last year, “represents the triumph of reverse-chronology, where importance—above-the-foldness—is based exclusively on nowness.” Hashtags are a way of capitalizing on that nowness, a way for readers to make their preferences known in an era when many news organizations lack an ombudsman and individual outlets’ “most read” lists fail to capture the breadth of what most of us are reading online.

#YesAllWomen made it almost obligatory for the mainstream news outlets to at least acknowledge the “feminist response” to the shooting—that the killer’s violent behavior was an aberration, but one with roots in male entitlement that most women would describe as routine. Time catalogued the best hashtagged tweets. The New York Times devoted a whole national news story to the hashtag and the sentiment behind it. Countless digital outlets published opinion pieces on the subject, which used not just the shooting but the hashtag response as their news hook.

Contrast that response to just five years ago, when George Sodini perpetrated a gender-based massacre and left behind videos and statements about his hatred of women. This was 2009—blogging was mainstream but Twitter had yet to take off, even among journalists. And although some feminist writers drew #YesAllWomen-type conclusions about Sodini’s violence, most mainstream news articles failed to connect Sodini’s affiliation with the men’s rights movement to more widespread misogynistic cultural attitudes. This time around, activists are using #YesAllWomen to advance a particular perspective on the crime. (And others, encouraged by a father of one of the victims, are pushing for political action with #NotOneMore.)

It’s too early to say whether the sentiment behind #YesAllWomen will have staying power, but it’s safe to assume the hashtag itself will fade away. Hashtags make for great second-day news analysis stories but have yet to achieve longevity. #BringBackOurGirls, another recent example of hashtag activism on behalf of hundreds of kidnapped Nigerian schoolgirls, made headlines when it found supporters as high up as the White House. The story has continued to get coverage in the international sections of the major US papers, but mentions have dropped off considerably—even though the girls are still missing.

In some ways, journalists should be grateful for hashtag activism. The trending hashtag is a way to figure out what the public wants to discuss and learn more about—with the added bonus that when journalists add more reporting and perspective to the conversation, their work gets duly hashtagged and receives an added boost. But in other ways, it’s just white noise. After all, you’re just as likely to see racist-joke hashtags trending on Twitter as you are to see under-covered, hugely important news stories like the disappearance of hundreds of Nigerian girls. And Twitter itself is an incomplete picture of the public’s interests: As of last year, only 18 percent of online adults were using it, but 58 percent of journalists were. For activists who want to demand journalists’ attention en masse, Twitter is far and away the best forum.

Ann Friedman is a magazine editor who loves the internet. She lives in Los Angeles