1. A computer-implemented method comprising: detecting internet protocol (IP) addresses for each of multiple different user devices that are connected to a network; determining that the detected IP addresses are within a range of IP addresses corresponding to a same network access device; determining, based on the detected IP addresses being within the range of the IP addresses corresponding to the same network access device, that it is appropriate to cluster network activity of the multiple different user devices based on the multiple different user devices accessing the Internet with the same network access device; aggregating network activity data for each of the multiple different user devices based on the determination that the different user devices are accessing the Internet with the same network access device, including: issuing a cluster cookie to each of the multiple different user devices; and collecting network activity data from the cluster cookie issued to each of the multiple user devices; receiving a request for content from one user device of the multiple different user devices; and responding to the request, including: generating and providing a response to the request based, at least in part, on the aggregated network activity for each of the multiple different user devices that was collected from each of the multiple different user devices using the cluster cookie when the request is received from a proper entity, and responding to the request without generating and providing the response based on the aggregated network activity when the request is not associated with a proper entity.