In some contexts, the term SEM is used exclusively to mean pay per click advertising, particularly in the commercial advertising and marketing communities which have a vested interest in this narrow definition. Such usage excludes the wider search marketing community that is engaged in other forms of SEM such as search engine optimization and search retargeting.
Often the line between pay per click advertising and paid inclusion is debatable. Some have lobbied for any paid listings to be labeled as an advertisement, while defenders insist they are not actually ads since the webmasters do not control the content of the listing, its ranking, or even whether it is shown to any users. Another advantage of paid inclusion is that it allows site owners to specify particular schedules for crawling pages. In the general case, one has no control as to when their page will be crawled or added to a search engine index. Paid inclusion proves to be particularly useful for cases where pages are dynamically generated and frequently modified.
Mobile devices have become increasingly popular, where 5.7 billion people are using them worldwide . This has played a role in the way consumers interact with media and has many further implications for TV ratings, advertising, mobile commerce, and more. Mobile media consumption such as mobile audio streaming or mobile video are on the rise – In the United States, more than 100 million users are projected to access online video content via mobile device. Mobile video revenue consists of pay-per-view downloads, advertising and subscriptions. As of 2013, worldwide mobile phone Internet user penetration was 73.4%. In 2017, figures suggest that more than 90% of Internet users will access online content through their phones.