Look at your smartphone. Scroll way down in the apps. See those five social TV apps you never use, or maybe the one you do use and the four you haven’t opened in months? What happened to those guys, anyway?

“The packaging of social TV became less relevant as Twitter continued its ascendancy,” explained Geoff Katz, whose company Watchwith syndicates content from NBCUniversal and Fox across apps like Viggle, Shazam and NextGuide. “If I want to know what everyone is talking about, I don’t need to do anything but open up Twitter. I don’t need to go to Zeebox or IntoNow.” The social TV phenomenon, Katz said, recapitulates what always happens whenever several companies pounce on the Next Big Thing—bigger players stake the winners (or startups go public), ”and in the interim a lot of companies raise and lose a lot of money.”

Shazam, which has raised more than $40 million in capital and is bearing down on an IPO, is selling product integrations to TV advertisers, said chief product officer Daniel Danker. “There were a lot of companies doing something I liked to call manufacturing a consumer need,” he said. Still, Shazam is growing by 2.5 million users a week and working with publishers to integrate closely into the shows that fit its mandate—awards and competition shows are its bread and butter largely because people will always want to know the name of that song playing in the background.

It’s difficult to tell which of the other social TV apps are still functioning as originally advertised. Some have evolved into other kinds of products, while others appear to be dying the prolonged death of the VC-funded tech startup. Katz is blunt: “One of the weird side effects of the venture-funded business of Silicon Valley is that you can appear to be in business for a very long time without doing anything.”

Miso was acquired by (and subsumed into) Dijit, whose product NextGuide just trawls existing social media accounts for recommendations. Umami has gone dark. TVplus radically converted its product to a publishing tool.

NBCU has a stake in Zeebox, and evp of digital ad sales Scott Schiller said the media conglomerate sold upfront packages that included Zeebox integrations. Yet the buzz-light Zeebox doesn’t show up in the top 300 entertainment apps in Apple’s store and is ranked No. 370 by analytics firm AppData.

Lately, NBCU’s app strategy is more focused on show-by-show deep transmedia integrations. “The latest of those is the Million Second Quiz app, which did exactly what we thought it would,” Schiller said. (Released in advance of the NBC quiz show’s Sept. 9 premiere, the app has already generated 5 million answered questions.)

And when it comes to more basic co-viewing, networks are predictably agnostic. “I don’t care where people engage with our content as long as I can be the curator of that conversation,” said Alexandra Shapiro, evp of marketing and digital for USA Network, which programs second-screen content for its original series. “This is a change in strategy—two years ago I would have said you have to drive people back to the mother ship; desktop, mobile, tablet, wherever it’s supposed to live. Now I feel like it’s wherever the user wants it.”