A working definition
Mobile advertising is paid media delivered to people on smartphones and tablets, either inside applications or on the mobile web. It covers formats built specifically for small screens and touch interaction: video, playable ads, native placements, interstitials and rewarded units.
What separates mobile advertising from digital advertising in general is not only the device. It is the measurement model, the inventory landscape and the behaviour of the audience — sessions are shorter, intent is more immediate, and the conversion often happens inside an app rather than on a website.
Where mobile advertising runs
In-app inventory sits inside third-party applications and is bought through mobile ad exchanges and demand platforms. Mobile web inventory behaves more like traditional display and video, accessed through the browser.
Each environment has different creative constraints, different measurement mechanics and different cost dynamics. A campaign that performs in-app will not automatically perform on mobile web, which is why environment selection is part of media planning rather than an afterthought.
How results are judged
Mobile advertising is usually measured with a combination of media metrics (impressions, CTR), cost metrics (CPI, CPA) and outcome metrics (conversion rate, retention, ROAS analysis).
Judging campaigns on installs alone tends to reward cheap, low-intent traffic. Connecting media to post-install events gives a truer picture of what the spend produced.