This ringtone ad is in a sports newsletter and shows a basketball star. The advertiser put it there to reach people interested in sports and music.
When an ad is part of a game, it's called an advergame. It can be hard to tell where the ad stops and the game begins.
When products appear in your favorite movie, show, or game, it's no accident. It's called product placement. Advertisers pay to have their products show up in the story.
Online ads can be silly, fun, and interactive. But their job is serious: to sell products.