If you are thinking of websites - Google may be the most visited.
Wikipedia Google Yahoo
Some newspapers have a section just for the most visited, or the most popular, websites for that week. Huffing-ton post and the record both have this feature.
The most visited kid websites are Club Penguin, Stardoll, Webkinz, etc.
Google, MySpace, Facebook,Yahoo
Facebook , google, yahoo ,wikipedia etc
That would be Logo, And http://www.thinkb4youspeak.com/
The Daytona International Speedway
In most browsers use the Ctrl+h keyboard shortcut.
landk
There are many ways one might find the most visited tech support forum. One can monitor and compare site traffic for many websites at the Alexa website.
http://www.filmcow.com/charlietheunicorn.html