[{'role': 'user', 'content': "Analyze the following clause from a privacy policy and determine if it's fair or unfair. Also identify any privacy practices mentioned: We will also use information about your particular device in order to show you adverts which work properly on that device, or to measure the effectiveness of our ad campaigns and we may also retain information about how many times you have seen a particular advertisement so we can stop you from seeing it too many times."}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]