Webpage domain monitoring is described. In an implementation, one or more web pages are obtained at a client, with each said web page including a plurality of content that is provided, respectively, via a plurality of domains. The plurality of domains that were used to provide the plurality of content is identified and a counter is incremented, respectively, for each identified domain. When the counter for a respective said domain exceeds a threshold, a notification is output by the client that indicates that the respective said domain has a likelihood of tracking the client.