Another change. If you want to insert a link, move the cursor to where you want it, and click on the icon in the edit bar that looks like a few links of chain. This prompts a popup screen where you enter the link and hit OK. n.b.: the prompt already includes "http:" so if you paste in the whole thing and wind up with two prefixes, you've got a broken link. The chain icon will look broken if your link isn't right.
Once you have the link entered correctly and hit enter, it will then prompt you to enter some text. So like in Gavia's story about Richeze from Tuttobiciweb, in this second prompt she'd want to type "Tuttobiciweb," making that the hypertext that appears in print.
The same editorial tools are available in comments as well. Chances are, your editing mode is defaulting to what's known as "WYSIWYG," what you see is what you get. This is more like editing in word. But if you're used to editing in HTML mode, click on the "Switch to HTML editor" button.