  Data collection purposes and their descriptions are presented on almost all
privacy notices under the GDPR, yet there is a lack of research focusing on how
effective they are at informing users about data practices. We fill this gap by
investigating users' perceptions of data collection purposes and their
descriptions, a crucial aspect of informed consent. We conducted 23
semi-structured interviews with European users to investigate user perceptions
of six common purposes (Strictly Necessary, Statistics and Analytics,
Performance and Functionality, Marketing and Advertising, Personalized
Advertising, and Personalized Content) and identified elements of an effective
purpose name and description.
  We found that most purpose descriptions do not contain the information users
wish to know, and that participants preferred some purpose names over others
due to their perceived transparency or ease of understanding. Based on these
findings, we suggest how the framing of purposes can be improved toward
meaningful informed consent.
