Ben Rubin, the cofounder of the streaming social video app Meerkat , had just arrived at SXSW in Austin, Texas , started handing out bright yellow T-shirts, and was enjoying his app’s massive buzz when he got the call. It was from Twitter: They wanted to let him know that Meerkat’s access to the Twitter graph was being limited within the next two hours.

We thought that we would at least get a week notice–a fair game.

“We are not naïve, we knew it was coming,” Rubin tells Fast Company. “We thought that we would at least get a week notice–a fair game.”

Meerkat borrows Twitter’s social graph so that you don’t need to recruit a whole new group of friends to watch your video live stream using the app. Instead, when you start a session, the app sends a notification to anyone with the app who follows you–a practice that critics have said is a bit spammy. Nevertheless, the app has struck a chord. Since launching two weeks ago, it has attracted celebrity users like Jared Leto along with coverage from CNN, The Guardian, and Time. Meerkat has also won the informal designation as SXSW’s “it” app of the year.

Twitter is also interested in live streaming, which is a natural evolution from the short-form video loops of Vine, which Twitter acquired in 2012. In January the company announced that it would acquire the live-streaming app Periscope. But that acquisition was only made official on March 13, and Meerkat’s access to the Twitter social graph followed soon after. A Twitter spokesperson cited the move as “consistent with our internal policy.”

Fast Company has reached out to Twitter for further comment.

While Meerkat users can still post videos on Twitter and log in using their Twitter credentials, the Meerkat app will no longer be able to automatically push notifications that announce the live event to all of a Meerkater’s Twitter followers. In other words, Meerkat will need to ask people to build their own social networks from scratch inside the app instead of using the network that its users already built on Twitter.

“Want to see something funny?” Rubin asks me.