We do copy various data by ctrl+c (or right click the mouse) for pasting elsewhere. This copied data is stored in clipboard and is accessible from the net by a combination of Javascripts and ASP.

Just try this:
1) Copy any text (by ctrl+c or right click the mouse and select copy)
2) Click the Link:
http://www.friendlycanadian.com/applications/clipboard.htm

3) You will see the text you copied on the Screen which was accessed by this web page.

Do not keep sensitive data (like passwords, creditcard numbers, PIN etc.) in the clipboard while surfing the web. It is extremely easy to extract the text stored in the clipboard to steal your sensitive information.