Facebook is pulling the mobile messaging feature out of its main mobile application, opting to put all of that functionality in its standalone Messenger app.

Instant messaging is clearly a focus for the social network, which has released several features to chip away at Twitter's dominance as the Web's platform for real-time conversation. This includes adding "trending topics" to users' News Feeds, as well as adopting the hashtag to show what other people are talking about on the site.

The announcement is not particularly surprising -- Facebook chief executive Mark Zuckerberg  mentioned the company's plans onstage earlier this year. The move is part of the company's plan to become a mobile app powerhouse. Zuckerberg has made building out a big portfolio of mobile apps a clear a goal for the company with major acquisitions of companies such as WhatsApp and Instagram.

The Messenger shift may be the first sign of cross-pollination with WhatsApp, which Facebook bought for $19 billion in February and whose customers are mostly international. In this way, Facebook could bring features from Facebook Messenger, such as the ability to use the app to contact people who don't have Facebook accounts, to a potentially broader audience.

The update, which will be rolled out to all Facebook users, is already available for some users in Europe,  TechCrunch reported

The change will likely irk some users by essentially forcing them to download yet another app, but there are some exceptions. TechCrunch reports that those with low-end Android phones that can't run Messenger won't see this update and that messages will stay a part of the company's recently launched Paper app. A statement to  Mashable from the company confirmed that iPad users won't be seeing the change, either. The Verge also reports that Windows Phone and tablet users will also be able to keep their messages inside the main app. Users will be able to switch between the main Facebook app and the messaging app via links in both programs, though it will add a split second or two to the normal routine.

Facebook could not immediately be reached for comment on the specifics of the rollout.

In comments to Mashable, Facebook said that the company has seen strong growth for its standalone Messenger app since launching the third version a few months ago. The upside of pushing all messaging functions into their own dedicated app is that power users won't have to dig into the second tier of the main app to access their inboxes. It also means that Facebook's main app may run a little leaner -- an important point, since the app was recently identified by the Guardian as a possible cause of iPhone battery drain.

But for the average Facebook user and the average mobile user, the pain of being forced to download another app for a core feature of Facebook -- and having to add even a few more moments to a Facebook conversation -- may not sit well.