Before Blue Birds Became X-tinct: Understanding the Effect of Regime Change on Twitter's Advertising and Compliance of Advertising Policies

Social media platforms, including Twitter (now X), have policies in place to maintain a safe and trustworthy advertising environment. However, the extent to which these policies are adhered to and enforced remains a subject of interest and concern. We present the first large-scale audit of advertising on Twitter focusing on compliance with the platform's advertising policies, particularly those related to political and adult content. We investigate the compliance of advertisements on Twitter with the platform's stated policies and the impact of recent acquisition on the advertising activity of the platform. By analyzing 34K advertisements from ~6M tweets, collected over six months, we find evidence of widespread noncompliance with Twitter's political and adult content advertising policies suggesting a lack of effective ad content moderation. We also find that Elon Musk's acquisition of Twitter had a noticeable impact on the advertising landscape, with most existing advertisers either completely stopping their advertising activity or reducing it. Major brands decreased their advertising on Twitter, suggesting a negative immediate effect on the platform's advertising revenue. Our findings underscore the importance of external audits to monitor compliance and improve transparency in online advertising.