On: Common Usability Mistakes In Web Design (includes Hacker News & Posterous)

" the only way to make the comment link targets bigger ... would be to add whitespace around them"

ORLY?

    a.big-click-zone {
        position: relative;
        left: -1em;
        padding: 1em;
        margin-right: -2em;
    }

Wouldn't this start to overlap with other links?

It could. You'd want to choose the expansion size judiciously, with less size for closely-packed links. Making the background light up during hovering would really help disambiguate click targets.