I was reading Doug Napoleone's blog (who also did a Python todo; looks like I may have started a micro-trend) and I noticed in his sidebar a link to something called XFN. Always curious about new technology and what people are developing, I followed the link and had a look.
Turns out it is a microformat for explaining your relationship to someone. Now I have avoided microformats up to this point as they seemed to be riding a buzzword wave of popularity. But XFN seemed somewhat interesting (even if the page that led me to it didn't use it, Doug =) as it was geared towards marking up links to other pages to describe your connection. Normally this wouldn't be a big thing, but it makes sense for blogrolls.
When you bother to list blogs to actual people (I am using the term "blog" to mean an online journal maintained by a person that at least on occasion discusses their personal life and thus is not always about work), it is nice to know the connection between the person with the blogroll and the person on the other side of the link. I could link to anyone, but I would hope that people who like my blog or know me would care more about links to blogs of people I consider a friend or an acquiantance than ones to total strangers. And so the idea of XFN makes sense to me (and makes me wish someone would implement a Blogger page element for blogrolls that used XFN to make it easy to use).
And this is what led to the exploration of microformats. Basically they seem like a more usable version of the Semantic Web, which I like. Having done a paper on ontology languages (e.g., OWL) I never really jumped on the web ontology bandwagon for the Semantic Web. But I like the idea of being able to glean information automatically from a web page. Microformats seem like a reasonable solution for that.
But then I started to consider what is required in order to use them. Every time I do a link to someone's blog on Blogger (or any other WYSIWYG blog editor for that matter) do I want to go into the raw HTML and add the proper markup to implement XFN? No. But would I be willing to do it for information that I don't have to edit often or is auto-generated? Yes.
In the end the usefulness of microformats, for me, is whether I can write the information once and then forget it. Otherwise it must have tool support to make it easy to add the information. I am not about to edit raw HTML constantly to support a microformat.
In the end, without tool support, I could see myself using hCard, XFN, hResume, and rel-home. All of the other ones would need tool support to make me want to bother with them. Although if they have an icon at least it lets people know I bothered to put the effort into supporting the format and thus gives me a little bit more motivation. =)