Characterizing Early Electoral Advertisements on Twitter: A Brazilian Case Study.

Some countries impose strict regulations regarding the distribution of electoral advertising during election periods. This is the case of Brazil, where electoral ads distributed before a predetermined period (called early ad ) are prohibited by law. Whereas the enforcement of such regulation on traditional mass media technologies (e.g., radio and TV) is common practice in the country, the same is a very challenging task for content shared on social media platforms, mostly due to the lack of proper tools to automatically identify content containing (early) electoral ads. This study aims to develop fundamental knowledge about characteristics of textual content containing early ads shared on Twitter, so as to drive the future design of effective detection tools. We offer a broad characterization of the textual content associated with a set of early electoral ads shared on Twitter in pre-election periods of three recent elections in Brazil, comparing their textual properties with those of other (non ads) tweets. Our main findings are that ads tend to have a negative or neutral sentiment, a certain syntactic structure, while most tend to explicitly mention a candidate or party to be chosen or avoided.