Web traffic per site was the first place I noted a power law distribution in the web. Back then (1997?) Alexia used to have a chart showing this. This chart illustrates that. It’s taken from this data source, it’s the table in that press release labeled “U.S. Top 50 Internet Properties”).

The vertical axis is visitors per month, and horizontal is the rank. The top three, who are neck and neck, are AOL, MSN, and Yahoo. The top of the chart would be 100 million visitors per month!