Towards transparency and privacy in the online advertising business

Independent Auditing of Online Display Advertising Campaigns

Authors: Patricia Callejo, Ruben Cuevas, Angel Cuevas, Mikko Kotila

Partners involved: IMDEA, UC3M

Proceeding: HotNets ’16 Proceedings of the 15th ACM Workshop on Hot Topics in Networks, Pages 120-126

DOI: 10.1145/3005745.3005752

Abstract: The reported lack of transparency of the online advertising market may seriously affect the interests of advertisers. In this paper, we present a novel methodology that allows advertisers to independently assess the quality of display advertising campaigns. This methodology also serves to audit the accuracy and completeness of reports delivered by the vendor responsible for running a campaign. We have applied our methodology in 8 display ad campaigns configured in Google AdWords, which overall produced 160K ad impressions displayed in more than 7K publishers. Our results reveal that AdWords seems to provide incomplete information to advertisers. Specifically, we found that: (i) AdWords did not report 57% of publishers where ad impressions from our campaigns were delivered, (ii) AdWords reports a large fraction of contextually meaningful impressions based on (non-disclosed) criteria different from the publisher’s theme, (iii) higher CPM investment does not lead to get impressions delivered to more popular publishers, (iv) AdWords does not offer default control of frequency cap, (v) around 10% ad impressions in two of our campaigns were delivered to IP’s from Data Centers. The industry considers these IPs to be likely related to fraud. These findings should contribute to open a debate between advertisers and Ad Tech vendors to standardize the utilization of independent auditing methodologies as the one presented in this work.

Research highlights:

  • We describe a methodology to monitor the online advertising ecosystem from the ads delivered from advertisers.
  • This methodology can serve to better understand the online advertising ecosystem and its functionality and also to assess which information a normal advertiser can retrieve from a user when the advertiser’s ad is displayed to the user.
  • Using this methodology we also analyse different aspects of the lack of transparency in the reporting of advertising providers.

Read the entire paper here.

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