Alex Faaborg, of Mozilla, has written an introduction to Microformats. It is basic stuff, but gets interesting at the very end with his section on The Web Browser as an Information Broker (Firefox 3?):

Much in the same way that operating systems currently associate particular file types with specific applications, future Web browsers are likely going to associate semantically marked up data you encounter on the Web with specific applications, either on your system or online. This means the contact information you see on a Web site will be associated with your favorite contacts application, events will be associated with your favorite calendar application, locations will be associated with your favorite mapping application, phone numbers will be associated with your favorite VOIP application, etc.
This is going to change the way we interact with data on the Web, and it’s something that I am going to be blogging about all this week, stay tuned.
Microformats are practical, and it would be fantastic to see rich support for them in applications other than those in the know hacking around.
Instead of looking for an “About” link on someones blog, if they have info about themselves tagged, the browser can let us know (as it lets us know that there is an RSS feed).
