It's actually more difficult to answer your question than it is to do, because of the fact that HTML code is legal in comments, so will be performed (and thereby rendered invisible) without elaborate subterfuge.

here's one way to do it:

<a href="WEB-ADDRESS">LINK-WORD</a>

At the top of the comment screen is a little row of mystic symbols.

If you look carefully, you can see that the eleventh and twelfth of these are < and >

After entering a bit of HTML, simply go back and replace every one of these "angle brackets" (or "greater than" and "less than" signs) by highlighting it and clicking on the corresponding mystical symbol.

Of course, one could also type these "escape sequences" in directly, but where's the fun in that?

Here's what a single instantiation of this technique looks like in real life:

Google Maps

On the other hand, third from the end of those mystic symbols is a little globe (or something like a globe: ). If you click on this symbol, a little dialogue will pop up and ask for two things: A web address (called a "link ref" in the dialogue), and a title text (that's the bit what will be visible in a tooltip one might see by hovering your mouse pointer over the link). When you've finished, simply click on "OK" and you're almost done. Your link will be created and the cursor placed where you must enter the text you want to appear on the actual screen, which can be a little confusing, but there you go. If you forget this step, your link will be created but no one will be able to see or use it.

Here's a sample created with the "globe:"

This bit filled in after clicking the OK button

Although the last step is a little difficult to understand, once done a couple of times it becomes almost automatic, and keeps all those nasty bits of HTML code properly tucked away where you might modestly forget about them. No sense sullying one's mind with smutty HTML code and naughty escape sequences if one can decently help it.

I highly recommend that we all become familiar with what those symbols do, as they many of them do quite useful things in the twinkling of an eye what would take longer simply typing them by hand, even if you knew how to do it.

It's perfectly safe to experiment with these little buttons (provided at great expense and trouble by site management, bless them) and look at their effects using Preview, and as long as one navigates away from the experimental reply or post before actually posting, no harm's done then, is it?

Cheers,

Liobhan