Flashes the pinned site taskbar button.
Returns one of the following values.
S_OK The operation completed successfully. E_NOTIMPL This method is not supported on Windows CE.
Use msSiteModeActivate to notify the user of important application events. This method flashes the taskbar button 20 times, then highlights the button continously until the window comes to the foreground. If the window is already in the foreground, this method does nothing.