Advertising is in constant development, and the language of advertising is adapting on an ongoing basis. Linguists all over the world have attempted to classify and analyse speech strategies used to create the most persuasive advertising text. The present article focuses on the linguistic strategies applied in online social advertising, such as strategies of warning and argumentation in general and the strategy of persuasion in particular. The study identifies the strategy of persuasion as the most popular in online social advertising. The author identifies the tactics instrumental in achieving the main goal of social advertising - encouraging action to the advantage of the advertiser - as well as a wide range of advertising avenues. The article analyses online advertisements using the methods of quantitative, cognitive and discursive analysis and drawing on the data retrieved from British and American website offering online promotional materials.