Search engine advertising is marketing on the Internet. It is a type of e-marketing, which in turn is a type of e-commerce. While at first the confusion of experiments, beta versions of websites, search engines and other online devices cause marketers to consider this world of the Internet unknowable and perhaps too unpredictable, there is now a growing body of work to which marketers are now paying attention in order to develop online marketing programs. The most known tools to marketers in the mid 2000s are currently tools grouped into 2 fields: online advertising and search engine optimisation.