Recently, as I decided to get involved in the design of my personal page, I learned how to represent semantic markup on a web page. I would like to share a few things about writing and parsing semantic information in this format. I have the intuition that it is only the beginning and that there will be more and more formats to describe who you are, what do you do, who your are related to, where you link to, and engines that gather these informations.
The information displayed is useful as it is a way to markup semantic relations, so that named entities are correctly identified. By search engines for instance : Google supports several formats, including hCard, and there are more specific search engines which aim at gathering informations such as a contact or a product list starting from this kind of markup. For a comprehensive list see here.
Now, if you are interested in parsing microformats, there are several tools. Among them, my pick: xfn-spider to crawl the web, get and visualize a tag crowd, a Firefox add-on to show and export microformats and a Perl module to parse them. Here is a complete list of the different tools.