Graphic novels at impressive publishers aside, comics are still considered children’s fodder and not to be taken too seriously. Still, comics vocabulary is consistently used in mainstream media to convey certain messages. For example, speech balloons are the most common and easily understood visualisation of oral communication. Moreover, since they are visual elements themselves,the balloons can convey different and conflicting messages in their shape and in their contents, resulting in rather humorous effects, as these examples show.
(from Ads of the World)