Back in 2005, a collection of talented web designers & standards coders took a shot at redesigning Jakob Nielsen's Alertbox. It was one of my first lightbulb moments where I realized the difference a bit of weight variation and vertical spacing could make. This is not an example of typographic elegance, but it's utilitarian, extremely readable, and appropriate to the material.

dt {
    font-size:75%;
    font-weight:bold;
    margin:1.5em 0pt 0.5em;
}

p, dd {
    font-size:75%;
    line-height:140%;
}

.thumb {useit_style.css (line 27)
    float:right;
    margin:0pt 0pt 0pt 0.5em;
}

body {
    font-family:Verdana,Helvetica,sans-serif;
}

This screenshot brought to you by the letter S, for Skitch.

(The New Typography is a series of posts of indeterminate usefulness showcasing interesting uses of typography online and how the designer implemented them. Type-as-image need not apply.)