[{'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: 4. California Do Not Track Notice We do not currently respond or take any action with respect to web browser "do not track" signals or other mechanisms that provide consumers the ability to exercise choice regarding the collection of personally identifiable information about a user\'s online activities over time and across third-party web sites or online services. We may allow third parties, such as companies that provide us with analytics tools or advertising services, to collect personally identifiable information about a user\'s online activities over time and across different web sites when he or she uses the Service.'}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]