Is there any reason for the <u> tag to exist? Underlining text was a means to highlight typewriting text. Typewriters, as useful as they were, were limited to a single font and size. Underlining text in these pre-published manuscripts was a kludge, allowing users to emphasize a particular portion of the text.
We understand why <u> was initially created: the web was originally conceived as a means for academics to exchange ideas. Since academic papers used underlines as a means of emphasizing reference titles; and since the people who created the original web standards still thought in terms of the typewriter they naturally included the <u> tag.
However a decade has gone by since Mosaic / Netscape revolutionized the web. What do we need the <u> for? Underlines are the default means of displaying a link and will remain that way for the foreseeable future even though underlines deface the types’ descenders. Still, usability trumps aesthetics in this case. As a result of underlines being used (almost) exclusively to designate links few professionals use the <u> tag anymore except when designers mean to evoke the look and feel of typewritten text.
This is a minor issue as there is no overriding reason to pull the <u> tag. Still, Web Standards are an evolving project – and this kludge from a bygone era needs to go.