I primarily use the Opera Web browser. Being the cheapskate that I am, I use "sponsored" mode, in which I don't have to pay for the program, but a relatively small banner ad appears in the upper-right corner of the user interface. It's easily ignored, unless it flashes madly.
For the past few weeks, I've been noticing more and more German-language ads appearing up there, and sometime this week I noticed that I wasn't getting English advertisements anymore (other than the ones from Opera itself). I barely remember any German from college; just enough to know that the most frequent banner is pitching cellphones from €1.29 (per day, I assume).
This morning, they broke up the monotony with an ad in French.