HTML magic tricks trick tricks web site visitors into executing shell commands without their knowledge. Linux users especially have to be careful what they copy and paste. Windows and Mac OS X users are usually harder to get users to open a command line window and paste commands into it. For many Linux users, this behaviour is still a normal thing to do. This could delete all of the user’s data or send them to a server on the public internet. The trick is by no means new, but it is currently being demonstrated again on several web sites.”]
Source: http://www.h-online.com/open/news/item/Old-tricks-are-new-again-Dangerous-copy-paste-1842898.html