An old way to underline. To cite the jargon file: Also, it is common to use bracketing with unusual characters to signify emphasis. The asterisk is most

An old way to underline. To cite the jargon file: Also, it is common to use bracketing with unusual characters to signify emphasis. The asterisk is most common, as in “What the *hell*?” even though this interferes with the common use of the asterisk suffix as a footnote mark. The underscore is also common, suggesting underlining http://catb.org/~esr/jargon/html/writing-style.html http://catb.org/~esr/jargon/html/writing-style.html