Brief:

• Among chat apps, Facebook Messenger dominates the U.S. market with 125.4 million users this year, up 7.5% from a year earlier, according to a new benchmark report from eMarketer. However, eMarketer lowered its estimates of Facebook Messenger growth through 2021, as data indicate that teens and adults ages 18-24 are engaging less with the platform in favor of Snapchat and Facebook’s Instagram.

• Americans will use an average of 20.7 apps a month this year, and that number will decline in the next few years as smartphone users concentrate their usage among fewer apps. Weather apps are the most popular category this year with about 157.4 million Americans using a smartphone to check forecasts at least once a month, up 7 percent from a year earlier.

• Maps are the second-most popular category with about 142.9 million monthly users this year, up 7.8% from 2016. Sports apps are forecast to grow 9.8% to 42.8 million people in 2017 from a year earlier, eMarketer said. The sports category includes apps from news providers such as ESPN, NBC Sports, NFL Mobile, fantasy leagues and live streaming of games.

Insight:

The news that Messenger's growth is slowing is surprising given that messaging apps overall are so popular and that Messenger has been a big focus of Facebook's monetization strategy with the launch earlier this year of a more robust ecosystem, including chatbots and 2-D codes and the more recent global roll out of ads. However, as the messaging space has matured, consumers are increasingly moving past basic texts and looking for a richer, more visually oriented experience, which both Instagram and Snapchat offer.

The news could provide Snapchat with a much-needed boost, as it has also been dealing with slower-than-expected user growth. Meanwhile, Instagram — also owned by Facebook — continues its phenomenal growth with users, brands and influencers.

The eMarketer report also points to how important in-app advertising has become for mobile. Greater app usage will help to drive mobile ad growth to $45.3 billion this year, and by next year in-app ad spending will make up 81% of all U.S. mobile ad spending, eMarketer estimates. The greater spending on in-app ads will slow the growth of mobile web ads, which are expected to grow in the single digits to $13.1 billion this year. App developers will put greater marketing efforts into boosting downloads, with app install ad spending jumping 29% this year to $7.57 billion.

The report also forecast that the news category will grow 8.9% to 84.6 million Americans using an app at least once a month for updates, but growth is being stymied by Facebook, the social network that is a popular source for reading and sharing news.