The fee structure is both a filter against superfluous submissions and a revenue generator. Typically, the fee covers an annual subscription for one webpage, which will automatically be catalogued on a regular basis. However, some companies are experimenting with non-subscription based fee structures where purchased listings are displayed permanently. A per-click fee may also apply. Each search engine is different. Some sites allow only paid inclusion, although these have had little success. More frequently, many search engines, like Yahoo!, mix paid inclusion (per-page and per-click fee) with results from web crawling. Others, like Google (and as of 2006, Ask.com), do not let webmasters pay to be in their search engine listing (advertisements are shown separately and labeled as such).
Search engine optimization consultants expanded their offerings to help businesses learn about and use the advertising opportunities offered by search engines, and new agencies focusing primarily upon marketing and advertising through search engines emerged. The term "search engine marketing" was popularized by Danny Sullivan in 2001 to cover the spectrum of activities involved in performing SEO, managing paid listings at the search engines, submitting sites to directories, and developing online marketing strategies for businesses, organizations, and individuals.
There are many reasons explaining why advertisers choose the SEM strategy. First, creating a SEM account is easy and can build traffic quickly based on the degree of competition. The shopper who uses the search engine to find information tends to trust and focus on the links showed in the results pages. However, a large number of online sellers do not buy search engine optimization to obtain higher ranking lists of search results, but prefer paid links. A growing number of online publishers are allowing search engines such as Google to crawl content on their pages and place relevant ads on it. From an online seller's point of view, this is an extension of the payment settlement and an additional incentive to invest in paid advertising projects. Therefore, it is virtually impossible for advertisers with limited budgets to maintain the highest rankings in the increasingly competitive search market.
Small businesses also use social networking sites as a promotional technique. Businesses can follow individuals social networking site uses in the local area and advertise specials and deals. These can be exclusive and in the form of "get a free drink with a copy of this tweet". This type of message encourages other locals to follow the business on the sites in order to obtain the promotional deal. In the process, the business is getting seen and promoting itself (brand visibility).
Digital marketing poses special challenges for its purveyors. Digital channels are proliferating rapidly, and digital marketers have to keep up with how these channels work, how they're used by receivers and how to use these channels to effectively market things. In addition, it's becoming more difficult to capture receivers' attention, because receivers are increasingly inundated with competing ads. Digital marketers also find it challenging to analyze the vast troves of data they capture and then exploit this information in new marketing efforts.