Once upon a time, a viral hit had the chance of sticking. After Twitter blew up at South by Southwest in 2007, the app continued to grow. Now Twitter TWTR is a $30 billion publicly traded company. Two years after Twitter’s breakout success at SXSW, Foursquare did the same thing. It had a long reign of popularity before it drifted off the hype cycle.

Today, the hype cycle that propelled Twitter and Foursquare into the mainstream has a much sharper edge. Apps can explode in popularity faster than ever, which means they can burn out just as fast. Hot new apps look more like blips in the news cycle than actual companies. Today, if an app goes viral, it’s probably doomed.

Think about some of the biggest viral hits of the last few years. Remember Yo? Remember Ello? Remember Secret? Remember Frontback? Remember Draw Something? Remember Turntable.fm? Remember Chatroulette?

Many of these apps are still around, but the excitement around them has faded and the users have lost interest. Frontback’s rankings in the App Store, according to App Annie, peaked in April of last year. Yo peaked in July and has steadily declined since. Secret peaked in August.

The rate of consumption (and the subsequent discarding) of new apps is accelerating. Chatroulette had nine months in the spotlight. Turntable had around a year. Draw Something only had six weeks. Frontback was hot in the tech scene for a few months. Same for Secret. Ello and Yo each had a week.

That brings us to this this week, where I’m entrenched in the mecca of viral hits and social media noise: South by Southwest. For the first time in three years, there’s actually a breakout hit. Meerkat, a livestreaming social media app, has exploded thanks to a heavy reliance on integration with Twitter (and a striking similarity, in functionality and logo, to Snapchat). Since launching in late February, the Meerkat has climbed into the top 100 social networking apps in the U.S. The app is perfectly suited to a festival like SXSW: it’s social, it’s live, it’s fun, and it’s frivolous. It is the topic of conversation at parties. The stakes could not be higher.

But it also might be doomed. Today, as first reported by BuzzFeed, Twitter will no longer allow Meerkat to import a user’s follower lists from its service. In other words, Meerkat has been cut off. Importing Twitter’s social graph is a big part of how Meerkat went viral. Without this functionality, Meerkat users must add friends manually. That creates a barrier to making the app useful right away. The move is “consistent with our internal policy,” a Twitter spokesperson told Fortune. (Notably, Twitter recently acquired a competing livestreaming app called Periscope, which has yet to launch.)

It’s possible this could kill Meerkat”s chance at success. It’s also possible that Meerkat’s viral success would have killed it, regardless of Twitter’s power move. As Yo, Ello, Secret, Frontback, et al have shown, app users are a fickle bunch.

A year ago, I interviewed Ian Bogost, game designer and professor of interactive computing and literature, media, and communication at Georgia Institute of Technology, on this topic. His comment rings even more true today: “Those sorts of consumer shifts used to take years or decades, but now they can happen in months or weeks or days, and we’re becoming accustomed to that idea.”