As we rode light rail trains around Kuala Lumpur, I noticed that ads were on the ceilings of the train cars. It seemed that companies rent ad space on entire trains. The outsides and insides of a train are completely wrapped in advertising for one company. Sometimes ads even cover parts of windows.
In this case, the company had something to do with preventing computer viruses.
I briefly raise these questions: How much advertising is too much? What if these ads help the train fare to be lower? And are the ads even effective? (I will answer that one — I’d guess that train users see them once and then the ads become invisible.)