Final answer:
Television advertising is not a category of online advertising. Online advertising encompasses display advertising, search engine marketing, and social media advertising.
Step-by-step explanation:
The category that is not a part of online advertising is television advertising. Online advertising typically includes categories such as display advertising, search engine marketing, and social media advertising. Television advertising, while still relevant, has seen significant declines in revenue due to changes in consumer behavior and the rise of digital media.
With the advent of technologies that allow consumers to skip or avoid traditional advertisements, companies have had to adapt by finding new ways to reach their audience. Online platforms have become a crucial part of advertising strategies due to their ability to provide targeted messages to a diverse and often more educated audience. In contrast, television advertising, although still used, especially in political campaigns and certain demographics, does not fall under the online advertising umbrella.