HTML or HTM just has the IE Icon assigned on your System. My system shows Firefox for HTML. Don't give it a worry.
here is an example of an external Link
Code:
<a href="http://www.webscription.net">http://www.webscription.net</a></b>
The Blue part is the visible TEXT. The text does not have to match the URL, but it is nice to supply the comfort factor that you are not hidinf somethig dastardly