Google's Gmail Android app adds mandatory adverts

Google's Gmail Android app starts showing in-line adverts that cannot be switched off. Photograph: Ruud Caris/Android World

Adverts have started appearing in some regions within Google's Gmail app for Android that cannot be turned off.

According to Dutch Android blog Android World, the adverts initially appear in-line with emails inside the "Promotions" inbox of the Gmail app.

The "Promotions" inbox, part of Google's algorithm-powered inbox filtering system that was released in July, can be turned off within Gmail's inbox settings on both the desktop and the Gmail app for Android.

Implementation is crucial

It's unknown whether the adverts will be restricted to the "Promotions" inbox, or whether they will appear in other inboxes within the Gmail Android app.

"The implementation of the adverts within the mobile Gmail apps will be crucial, due to the impact they could have on the limited real estate available on mobile devices, " said Ian Maude of research firm Enders Analysis talking to the Guardian.

It would have to be fairly bad to make people switch

However, Maude explained that, "it would have to be fairly bad to make people switch email providers as there's quite a lot of inertia - including the hassle of notifying all your contacts of a new [email] address - preventing easy switching."

Code suggesting that Google was set to bring adverts to its Gmail app for Android was found in the most recent version of the app last week, with options to save, share or dismiss them as messages.

* In September, Google introduced Hummingbird, its biggest search algorithm change in three years, to make its core search engine better at answering your longer, more complex and spoken queries.