Microformats contribute to the principles of a semantic web in a very useful way. With microformats any structured or unstructured information on web pages can be given a meaning. Name and address information anywhere on the page can be tagged as belonging to personal contact information. Words like “Walter Soldierer” are meaningless to a program, but they can be turned into something the program can deal with by tagging them with microformats. The following code makes the words semantically belong to a “formatted name” (fn):

<span class=”fn”>Walter Soldierer</span>

How do you tell if a web page uses microformats?

You can’t tell by just looking at the page. You either need to view the html source code or run a tool to inspect the page. Check this blog’s About page, for example. There is structured address info, but even though it is heavily microformatted as a hCard, it does not look special.

So what are microformats good for anyway?

Microformats allow programs to categorize the information on a web page, find related content, and offer useful extensions. Here are some typical examples for the 3 fundamental data types that microformats are most used for:

WHO?

By exporting a vCard, address information on a web page can be added to program’s list of contacts.

WHEN?

Event information can be added to calendar applications.

WHERE?

Location information (city, street) can be used to display a map or directions.

When microformats are widely used, you no longer register an event at upcoming.org. Instead you only add it to your own web site’s events page, properly tagged as an event using microformats. There it will be found by upcoming.org, Google, and many other sites, and listed together with tens of thousands of other tagged events that were published anywhere on the web.

What applications use data tagged with microformats?

Search engines are already taking advantage of microformats. An experimental Yahoo site called Microsearch nicely shows what can be done. The engine extracts microformatted information from pages and gives it a prominent place in the search results. Properly tagged location data shown on a map, providing a user experience similar to mashups.

Another really nice example of how software can take advantage of microformats is Operator, a Firefox 2 add-on to detect microformats in web pages. Now that I have used Operator, I really look forward to Firefox 3’s native microformat support. Operator lets you view and export the tagged data. It nicely integrates with applications like Google maps, Yahoo maps, Delicious, Youtube, and Upcoming. Operator can even search Flickr photos that match the tags used in your blog post.

Operator add-on at work

Are microformats an eMarketing tool?

Very much so. Internet users consume information with the tools that they find most convenient. Microformats make information accessible to such tools.

If you don’t use email newsletters and RSS feeds to promote your brand, a significant part of your target audience will not receive your message. Microformats add more choice to how users receive information, just like email and RSS.