be an attempt to manipulate the search results in search engines like Google, Yahoo, Bing or the search feature of Facebook. In most cases, a certain item is promoted, but in some rare cases, the goal actually seems to be to push unwanted result items back in the result list.

These campaigns appear to assume that search engines learn: if for given search term, a high number of users click on a particular result item, then that result item must be a good result for the search and therefore it will be listed early in the results listing. While the actual algorithms search engines use are proprietary and unpublished, it is known how they work in theory [@Buettcher2016]. It is thus plausible that they can be tricked in this way to a certain extent. We know that user behavior is taken into account in Google, for instance, as [@Clark2015] reported that Google’s novel AI solution, BrainRank, was the third most important factor (the technical term is “signal”) when ranking pages. We also know that it learns from user behavior, hence it is plausible these systems can be tricked through paid user behavior simulating genuine interest.

A search and engage campaign 