Google is ready to start showing ads in its Gmail app on Android smartphones, according to new code discovered in a recent update.
Artem Russakovskii of Android Police unpacked the .apk (Android Package) file for version 4.6 of the Gmail app for Android, currently deployed across handsets running Android 4.0 upwards, and discovered multiple mentions of adverts within the application code - including references to saving ads as messages and dismissing them.
Google's mobile apps for both Android and iOS have thus far stayed ad-free, unlike their desktop counterpart. That has included adverts above the Gmail inbox since 2004, and since May has added email-like advertising messages that appear within the 'Promotions' tab.
In August Google implemented mobile ad serving within the Google Maps app on both Android and Apple's iOS, with adverts showing up against searches for places, services and landmarks along with search results.
Money for mobile
Google is increasingly looking to make money from its mobile properties. YouTube's mobile ad revenue has also recently taken off, generating as much as £226m in the first quarter of 2013 alone.
"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.
"It will be a balancing act between designing a system that is prominent enough to attract attention while not annoying users; it has to be intrusive enough to garner a response," Maude said.
But he thinks Google will have some room to manoeuvre in how it presents any ads: "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."
Mobile: growing in importance
Mobile web use is rocketing, especially in the UK, with the number of daily internet searches from mobile devices expected to surpass daily desktop searches by 2014.
In 2010, Google bought mobile advertising company AdMob to boost the company's mobile advertising capabilities.
Google recently made significant changes to the way its AdWords advertising network operated with respect to mobile ads, giving advertisers greater control over individual ad spend on mobile devices, locations and times.
Cheap but plentiful
Ads within services like email and chat are generally of low saleable value, due to the fact that users aren't actively searching for outside information when they access their emails or engage in chat and are therefore less receptive to ads - they are very focussed on the task at hand.
"It'll be all about volume for adverts in Gmail," said Maude. "Google has the advantage of having many millions of users, who regularly check their email and therefore provide the potential for high frequency ad views."
"Google will have to stack them very high and sell them very cheap, but it could make a significant new revenue stream for Google," Maude concluded.
AdWords contributed the bulk of Google's $43bn (£26.5bn) advertising revenues in 2013, which itself made up over 86% of Google's total revenue, while mobile advertising is predicted to account for one-third of advertising spend growth in 2013, according to ZenithOptimedia's advertising expenditure forecast.
Asked whether and when ads would appear in the Gmail app, a Google spokesperson said: "we're always experimenting with new features, but have nothing new to share at this time."
• In July, a US scheme to intended to strangle illicit revenues blocked websites offering pirated content from displaying Google adverts.
