As a technological side-note, I'm also curious how the topic of implementing such styles plays in to the picture with semantic web coding. For example, I used the <cite> HTML tag to italicize Moby Dick above, and have practiced a similar method in the past when mentioning book titles (as opposed to using <em> or <i>). However I'm not positive that's really what <cite> was semantically intended for. From much of what I've read, it seems to have been introduced more for proper citation in the traditional sense – for attributing quotes and such – than it is for simply mentioning a book's name in passing.

Italics could work for titles and quotation marks for component parts (e.g. blog entries), as are commonly used for albums/tracks or journals/articles. Thus: 'I just finished reading "GIF, H.264, and Patents" on Daring Fireball last night.'

Using italics is, as you say, a stylistic convention, tied, among other things, to the language you are writing in.
For example, in Italian, titles of publications, be they books or magazines (and ships' names as well), would go in italics, but not articles, which would go between double quotes. Definitions too would go between double quotes, while the use of italics for emphasis was not common.
So, for websites, if they are in some way publications (as opposed to, say, brochures), I suppose you could use italics. The problem is that most often websites' names are hyperlinks too. That means they already have their styling distinct from the surrounding text. Adding italics to this styling can add visual clutter and reduce legibility.
As for what to use, the "i" tag is the only sensible one, maybe paired with an appropriate class.
I say this exactly because it is semantically neutral.

That makes sense for relatively straightforward cases, like blogs with editorial content. But do you think it should apply to all sites? Like, would you italicize Typophile? I have a hard time answering that question decisively, and could go either way.

And what about referring to the online publication of a news organization? The websites for newspapers often feature unique content and might be considered their own separate entities, but you rarely see something like "Khoi Vinh is the design director for NYTimes.com."

FWIW, here's what the Chicago Manual of Style suggests:

http://www.liu.edu/CWIS/CWP/Library/workshop/citchi.htm

If you are writing in English, you can't go wrong following their lead...

But note that that link is talking about formatting reference-list citations, not in-text references. (For example, the examples don't put quotation marks around journal articles but I assume it would be proper to do so where that title appears in the text.)

Edit: My lastest edition of Kate Turabian, Manual for Writers (which I think is a distillation of Chicago Style) says, in text, capitalize but do not italicize websites, and put individual article/page titles in quotation marks.

The W3C Recommendation for the cite tag specifies that it Contains a citation or a reference to other sources.

The Recommendation does not specify the type of the source.

An example:

As <CITE>Harry S. Truman</CITE> said,

<Q lang="en-us">The buck stops here.</Q>

More information can be found in <CITE>[ISO-0000]</CITE>.

Other XML schemas such as Docbook have much richer semantics than this.

Nick, I would add that HTML is mark-up language primarily for the display of information, and not for its semantics. As such it is not a commendable storage format for content that needs to maintain the kinds of distinctions you have specified.

That said, you could achieve the desired effect by including a class attribute of your own devising in each cite tag, and controlling the output via a CSS rule. This would also allow a cleaner conversion of your HTML into a semantically richer mark-up at some point in the future, should the need arise.

> Nick, I would add that HTML is mark-up language primarily for the display of information, and not for its semantics.

I would argue the opposite. That is why <strong> is used instead of <b> and <em> instead of <i>. <cite> is clearly to show a citation, not italicized text. CSS is the display element of the web, not HTML.

Better to have said "for information that is meant to be displayed" (i.e., on the web): stuctural and presentational semantics and not much more.

Still, the examples of the <strong> and <em> tags are in fact both presentational mark-up, rather than structural (much less lexical). They differ not in kind from <b> and <i> but only in degree of physical abstractness.

<b> and <i> are still valid tags, even in HTML5.

Thanks all for the technical insight. What I'll probably end up adapting myself is a custom class. Unfortunately, that doesn't answer the question of what markup to use to refer to books on Typophile (I'll probably stick with <cite>).

It also still leaves me a bit unsettled as to where I should even apply specialized typesetting or not – be it on my own site, Typophile, or any of the other places of varying code-flexibility that I might be writing. The recommendation Craig offers from Kate Turabian is a practical solution, but I can't help feeling that it implies an inferiority of any content that exists online… why should Huffington Post be treated any differently from New York Post?

When possible I typeset website names or URLs in a different color from the body copy. On the web, the anchor tag is best for website names.
I was just thinking how much more complicated it must have been to print long documents that require two or more colors before offset lithography became a standard printing medium. Would the typesetters of the first red letter bible know?

Yeah, I don't have any problems deciding how to typeset links, it's more an issue of figuring out how to typeset website names, regardless of if they're links or not – or if they're even in digital form at all.

The HTML 4 spec for CITE is, by general expert agreement, borked.

I just typeset names of Web sites with initial caps on all important words. If I have to typeset an URL, I use CODE online and Thesis Mono in print.

On internet, different colour is enough to turn it into a link, an on printed text, the www. usually differentiates the address without any styling. Bold or italic would only confuce, in my opinion.