What is the difference between “viewing advertisement” and “clicking advertisement” services?

In the “viewing advertisement” service, whenever a user sees an advertisement at any sections, it will be calculated but in the “clicking advertisement” service, users must click on the product link to be calculated.

It should be noted that if you just purchase the “clicking advertisement” service, your intended product will be displayed at the search and categorization pages, but purchasing the “viewing advertisement” service alone, will be useless, unless you have already purchased the “clicking advertisement” service. If you have both services together, the promotional product will be displayed in all sections of advertising on the site.