The reason SpyCop Cloak asks you if this should be allowed or not is because if an application is able to do this, it can continuously monitor the contents of the Windows Clipboard.
The application can also be notified of when the contents of the Clipboard have changed.
Some applications need to be able to monitor the Clipboard in order to function properly.
Spy Software, Keyloggers, Trojans & Worm applications monitor the Clipboard in order to track information as it flows through your system.
For example if a spy application was able to monitor the Clipboard it could monitor your bank account number if you copied it from a text file into the browser window.
In most cases this event should be denied unless you really trust the application that is trying to gain access to the Clipboard.
