Fast forward to Fox’s announcement last week that it would offer six-second TV spots to advertisers during NFL games and other sporting events. This comes after testing the format on the Teen Choice Awards last month. Fox was able to charge a relative premium for the six-second ads, which are about the same length as ads on YouTube, meaning a younger demographic can sit through them.

So why did Fox do this?

Survival.

With almost 16 minutes of commercial airtime per hour of programming, networks are struggling with dwindling audiences, and viewers who fast-forward through commercials when they pause live TV or when they DVR a show. From 2012 to 2016, the number of people without cable or satellite TV has increased by 8.4 million, and by the end of 2016, nearly 20 million households didn’t have cable or satellite TV. So with millions of consumers cutting the cord and migrating to other platforms like Netflix (NFLX) that are commercial-free, or even ad-supported platforms like Hulu, TV audiences are shrinking, while the cost per ad continues to rise.

Networks like Fox must think differently. Since their revenue model is at stake, they must provide value. By offering six-second ads, networks might be able to reduce the length of commercial breaks—especially in sports programming, which is already a source of fan frustration.

Both YouTube and Facebook have been pushing six-second ads. Facebook (FB) has noted that its users watch autoplay ads for 5.7 seconds, and a comScore study found that ads have be five to six seconds in length to have an impact on millennials. So there’s reason to believe this will work on TV.

Marketers have already been shifting toward 15-second spots for some time. According to Nielsen, in the first half of 2017, 15-second commercials made up 36% of all spots on TV, up 7% vs. 2014. And 30-second spots are down by 12%. Fox, which is known for its bold programming moves, is making an aggressive push to keep television relevant for advertisers.

This could represent a multi-billion-dollar gamble. For the nimble and agile advertisers, this could present an opportunity. However, brands must weigh the pros and cons. Not only is a six-second commercial slot cheaper, but it’s enough time to announce a product and a benefit of purchasing it. It forces brands to really think hard about what matters. Thankfully, though, TV is visual. Copy can be accompanied by dynamic and memorable images. This aligns with the behavior of millennial consumers who are used to communicating via short text or through social media apps like Snapchat (SNAP). Now campaigns have the opportunity to run in a more coordinated fashion across multiple communications channels.

For marketers, six-second ads risk reducing consumer engagement and fraying emotional bonds. And for some marketers, like drug companies that require substantial disclosures with every claim, six-second ads will be a non-starter.

Fox has already shared ideas of how these six-second spots can be placed during dead times within games to shorten commercial breaks. To maintain their profits, the CPM (cost to reach 1,000 viewers) for these six-second ads will be relatively high even though the absolute cost of the TV spot will be much lower. Nevertheless, six-second ads might be attractive to new advertisers who can’t afford the absolute costs of a sustained campaign of 30-second spots.

How likely is this going to catch on? Clearly, networks know something has to change. They have to rethink standards and keep advertisers buying during the up fronts. Initially, this might benefit existing brands with strong awareness. Clearly this is a first step. All the other networks will watch this closely to see if it sticks. If it catches on, Fox will be a hero.

Miro Copic is a professor of marketing at San Diego State University and CEO of BottomLine Marketing.