I've discovered an idea of microformats quite recently, and I was immediatelty charmed by its simplicity and elegance. Simply put, microformats are about formatting semantically united blocks of data so it will be easily understandable both by machines and by humans. Examples of the data which will benefit from this approach are numerous. Microformats.org - a site dedicated to microformats - lists almost a dozen already existing formats, including hCard - format for representing people and organizations, hCalendar - format for events and calendar entries and others. Microformats are based on XHTML - which allows them, on one hand, to be easily integrated into a web page, and, on the other hand, to be easily extracted from the page and processed by any program.
There are already several tools - most of them are stil beta versions, though - that are able to detect the presense of microformatted data on a web page and extract it. One of the examples of a freal-world usage of microformats is the way Technorati processes tags from blogs - rel-tag is one of the microformats!
One thing I am afraid of, however, is an uncontrollable proliferation of incompatible microfomats once the idea becomes popular. It's so easy to come up with your own format! This might render the whole idea unusable - but I do hope that it will not happen, and I am watching with interest all the new development in this area.
Technorati tags: microformats, web2.0