Publishers are increasingly looking to messaging apps like Snapchat and WhatsApp as a way to deliver news to young, smartphone-dependent audiences. And these apps have become popular enough that, starting this year, the Pew Research Center has begun breaking out their usage as “a separate kind of mobile activity.”

According to a Pew survey conducted this spring and released Wednesday, 36 percent of smartphone owners use messaging apps like WhatsApp, Kik (now valued at $1 billion), while 17 percent of smartphone owners use “apps that automatically delete sent messages” like “Snapchat or Wickr” (but it’s safe to assume most of that use is coming from Snapchat, which now claims at least 100 million users, not the encrypted messaging app Wickr).

Not surprisingly, these apps are most popular among a younger crowd: 49 percent of smartphone-owning adults ages 18–29 use messaging apps, Pew found, and 41 percent of that group uses “auto-delete”/ephemeral messaging apps like Snapchat. Still, a significant number of older people use such apps as well; nearly a quarter of smartphone-owning adults ages 50 and over use messaging apps, according to Pew.

A couple other bits from the report:

— 15 percent of online adults read or participate in discussion forums like Reddit and Digg, with that audience skewing male and young.

— Pew looked at the growth of several social media platforms and found Instagram and Pinterest growing particularly quickly; they’re used by 28 percent and 31 percent of online adults, respectively. Instagram, in particular, “continues to be popular with non-whites and young adults” and women.

Pew surveyed 1,907 U.S. adults ages 18 and older via phone for this research. The full report is available here.