Mobile Apps or Mobile Web? Both, Sometimes.

People are spending an increasing amount of time using apps on their phones, at the expense of the mobile Web. That’s worrisome, says Andreessen Horowitz’s Chris Dixon.

Could be.

But before you write off the mobile Web, remember that it’s possible to use both mobile apps and the mobile Web at the same time. As Daring Fireball’s John Gruber writes:

“On mobile, the difference between ‘apps’ and ‘the web’ is easily conflated. When I’m using Tweetbot, for example, much of my time in the app is spent reading web pages rendered in a web browser. Surely that’s true of mobile Facebook users, as well. What should that count as ‘app or ‘web?’”

Here’s an argument for counting them as “both, sometimes”: Quantcast, the Web measurement/ad company, says nearly a quarter of mobile Web views may be coming from in-app browsers running on Facebook or Twitter. That is: People who click on links and open up stories are in apps and on the Web, at the same time.

That data comes from a recent survey of Web traffic on Apple’s iOS machines, so it’s possible that the numbers might skew if you included Android devices as well. And since Quantcast only measures Web traffic at publishers who use its analytics software, it’s possible that the broader Web world would have different results.

Still, something to think about before you write an obituary for mobile websites. And it’s also a reminder of how powerful Facebook, and to a lesser degree Twitter, have become for traffic distribution.

Another reminder: Quantcast says social is now more important than search when it comes to referral traffic on mobile. This isn’t the first time we’ve heard this sort of thing. Here’s the breakdown:

This article originally appeared on Recode.net.