To add an external link in the Discussion board that will open without the warning bar, follow these steps:
1. type text into the message box
2. highlight the text to link
3. click on the 'globe icon' in the WYSIWYG editor to add hyperlink
4. add the URL in the hyperlink window
5. click on the checkbox next to 'Open Link in New Window'
6. complete any more text you want to add to the post and click 'Submit'