I've seen the MF people talk and have heard my own fair share of MF evangelism, yet haven't done anything about it fearing the gains aren't really worth the hassle. Does anyone use this?
BTW, from their website:
"microformats are a set of simple, open data formats built upon existing and widely adopted standards. Instead of throwing away what works today, microformats intend to solve simpler problems first by adapting to current behaviors and usage patterns (e.g. XHTML, blogging)."
/mp
It's sort of a chicken-and-egg problem, they're not hard to implement but there really isn't any sort of widespread adoption of microformat consuming software.
On the other hand, since microformats aren't widely adopted, there really isn't any need for people to download and install microformat consuming software.
Given a new project, I'd probably implement microformats where appropriate, but it's always pretty low on the priority list (I'll do it whenever I can get around to it).
I think almost anything you'd like to put into a microformat you could make something with a "full" format. hCard.. you could just make a simple vCard file. hCalendar? Make an icalendar file you update and link to it. The advantage to NOT using microformats is that you can use almost any application that supports calendar/contact etc information and point them at the "full" format instead of the microformat, which requires consumer applications to add more functionality.
To me, that's just the state of things now. I have no technical reason to not use them. I just think that if you just make the "full" format, applications consuming this information are more likely to support/handle it. Though the rel="me" stuff is extra information that you don't get from other things. I'd say use those since they're easy, and adds information that no other format/standard really does (that I know of).
Microformats are very useful. They give the benefits of machine-readable data without the need to duplicate your data (to have a version for humans and a version for machines) and learn lots of other formats and standards for publishing different kinds of information.
There are also a large and growing number of parsing services, for example Technorati provide services for converting hCard to vCard and hCalendar to iCalendar (see http://technorati.com/contacts/ and http://technorati.com/events/).
There's a summary of the benefits on the Microformats wiki: http://microformats.org/wiki/benefits
I think MF will get their breakthrough when Mozilla finally includes the great Operator extension (with less functionality of course, like only displaying MFs in the address bar if available) in Firefox.
If the users like it, the other browsers will most likely follow, and THEN it becomes important for developers to include MFs in their webpages.