The Big Picture on Microformats

The Big Picture on Microformats

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By John Allsopp

Published on August 28, 2006

Most web developers who read magazines such as Digital Web will be familiar with the term microformats, and might even have played around with hCards or tags. In fact, way back in November 2005, Digital Web was among the first to address this subject, publishing a great introduction by Garrett Dimon.

Few really dispute the potential of microformats, but all technologies, no matter their promise, live and die by their adoption. So, how are microformats faring a year or so after their coming-out party? Since microformats are markup, their impact is less obvious than, say, AJAX—whose dynamic visual effects are usually a bit of a giveaway. It may come as a surprise, then, that the level of adoption by tool developers, publishers, and aggregators is significant, and that you probably visit sites with microformatted content all the time, without even knowing it. In this article, we’ll review what people are doing with microformats right now, and finish up by looking at a couple of cool projects that might whet your appetite for microformats’ future prospects.

Chicken and Egg

I occasionally wonder who bought the first fax machine—what a remarkable act of faith. The fax illustrates an important phenomenon associated with many technologies—the network effect—where the value of a technology increases the more it is used. In trying to climb the slippery pole of the network effect, new technologies often face a chicken-or-egg moment. With microformats, content developers may ask, “If there are no services that take advantage of microformatted data, why should I use microformats?” Service developers may similarly ask, “If there is no microformatted data, why should I develop services in the hope it may one day be available?” As I’m about to demonstrate, microformats have passed this chicken-or-egg moment in a number of areas.

If you are a content developer, a tool developer, or a service developer, using microformats to add semantic markup your content offers significant benefits. Let’s take a look at what individuals, open-source projects, major-league content publishers (such as Yahoo!), and service developers (such as Technorati), are doing right now with microformats.


Most of us now rely on tools to do the heavy lifting for us—whether we use tools like WordPress or Moveable Type for blog posting, or Dreamweaver for design. While hand-coding microformats is relatively simple, many of the applications we use for markup, web design, and posting have added support for—or have plug-ins for—easily adding microformatted content.

The Web Standards Project Dreamweaver Task Force, in the shape of Drew McLellan, has developed a plug-in for Dreamweaver that makes it easy to add microformatted content to your web pages. This beta version extension helps Dreamweaver users insert hCard, rel-tag, hCalendar, rel-license, and XFN data into their documents.

WordPress, Moveable Type, Drupal, TextPattern, and other blogging and CMS tools offer plug-ins for adding a variety of microformatted content to blogs and other sites developed with these tools. A quick search will locate plug-ins to create just about any kind of microformat—reviews, calendaring, tagging, contact details, and more—for many CMS and blogging systems. also has several stand-alone creators for developing microformatted content. hCard Creator, hCalendar Creator, and hReview Creator allow you to develop complex microformats—simply enter the necessary information into a web form, and then paste the output right into your source code.

So, whatever your development methods, you’ll likely find tools to help perform the boring, repetitive tasks—such as translating nice, human-readable dates and times into ISO 8601 format, making microformat creation simple.


The earliest adopter phase of microformats—more or less until early this year—saw the majority of microformatted content developed by bloggers. Tagged content using the rel-tag microformat and XFN are the best examples of this, and, to a lesser extent, contact details using hCard. The last six months or so has seen the use of microformats tip over into decidedly mainstream situations, including widespread adoption at Yahoo!.

Several Yahoo! sites, including Tech, Local, Flickr, and Upcoming use various microformats in their publishing. Both Yahoo! Tech and Yahoo! Local use hReview for publishing reviews, while Yahoo! Local uses hCalendar for events, and hCard for contact details. Flickr uses hCard for profile information, as well as XFN. has more than a million events around the world marked up using hCalendar.

The beauty of many of these services is that while users generate content—for example, reviews—there is no need for these users to know anything about the underlying formats. The tools do the work of translating the content into the appropriate microformat.

It’s this significant adoption by publishers that is really driving the huge growth in microformatted content on the web.

Uncorking Microformats

One of the most innovative uses of microformats in the last twelve months has been the recently launched, great-looking Cork’d, a very Web 2.0 wine-oriented site. Cork’d, developed by the well-known author and designer Dan Cederholm of SimpleBits, and Dan Benjamin of Hivelogic, features hReview as the format for wine reviews, hCard for wine reviewers (anyone can sign up for a free account and review wine) and rel-tag for “tasting tags” (so reviewers can tag wines by flavor—such as pepper, berry, or moldy sock). Cork’d is a great model for the simple, elegant use of semantic markup that use of microformats enables. If you are working on or planning any kind of user-generated site, you’d be mad not to spend some time looking at what Cork’d does with microformats.


The real promise of microformats is that they enable decentralized development, content, and services. Until now, a great many review sites (such as Amazon book reviews or IMDB movie reviews), classified listings, social networking services, and other types of sites have been centralized—locking users and their content into a single service, rarely even providing an API so that developers can do interesting things with all that content. Think of classifieds sites, such as craigslist or Trading Post, or auction sites such as eBay, all walled gardens, where user-generated data is tightly controlled, and—in many cases—owned by the aggregators.

The recent explosion of map-based mashups shows the promise of what open data can enable when the walls to those gardens are pulled down. But open data requires standardized formats, such as microformats, to make it useful.

It’s in this area of aggregators and other decentralized services that the real promise of microformats lies. Already, Technorati tag searching has demonstrated the power of a simple standard format for tagging content—in the fifteen months leading up to April of this year, tagged posts indexed by Technorati grew from zero to 100 million.

But what’s happening with other decentralized services using microformats?

Recently, Technorati took the wraps off their Kitchen, which has a search engine specifically for microformatted content, including events in hCalendar, contact details in hCard, and reviews in hReview—all indexed from around the web. Now you can search for microformatted content no matter where it is published.

But coupled with this is something even more exciting: Pingerati. Pingerati passes information about microformatted content on to services that want to index it. Sites such as Eventful can ping Pingerati to obtain updates for its index of events that are in hCalendar format. This makes developing distributed services for microformatted content even easier—providing a centralized location for publishers to ping with updates, and indexers to check for new content, much like is available for blogs to ping when they are updated.

This type of distributed service hasn’t taken off yet to the extent that publishing microformatted content has; still, very promising services are already out there. Edgeio, a classifieds site, aggregates listings in the hListing proposed microformat, rather than forcing you to submit your listings to them. Edgeio also publishes the listings in this format, and—recognizing that not everyone has a site at which to publish their classifieds—allows you to publish classifieds at their site. Kritx, though just recently introduced, is an aggregator for reviews published in hReview format, with an approach similar to that of Edgeio.

It can only be a matter of time before aggregators and distributed services for microformatted reviews for restaurants, films, events, resumes, and other content take off. After all, microformatted content is found more and more often at individual blogs, at niche sites such as Cork’d, and at large scale sites such as Upcoming and other Yahoo! sites. It soon may be at your sites, too, if it’s not there already.

Cool stuff

I recently had the privilege to hear Lars Rasmussen, one of the original developers of Google Maps, speak about building maps. An interesting part of that story was that they never really thought of people doing mashups, and it took them by surprise. Now, a significant part of each day is spent looking at map mashups. In fact, Rasmussen says that an important reason for requiring an API key is so that they can keep track of popular mashups. Google’s open approach to allowing others to use their mapping data has created, in effect, a new category of web applications, and let them get the jump on a number of more established, well-resourced mapping applications. By giving open data on the web simple, established formats, we move one step closer to enabling a whole range of as-yet-unimagined mashups.

hCard Maps Mashups

A couple of cool projects illustrate how to take advantage of these new ways of working with data. One of the most prolific contributors to microformats the last couple of years has been Brian Suda. He’s the co-author of the hCard and hCalendar specifications, a contributor to a lot of the brainstorming associated with other formats, the author of an upcoming O’Reilly PDF book on microformats, and the developer of X2V. X2V is an online service that will take a page with, say, an hCard or hCalendar in it, and convert it to vCard or iCalendar format (the IETF formats on which these are based), and, depending on how your system is setup, these will automatically be opened in whatever software you use for reading these formats (Outlook, iCal, Address Book, etc.).

Here’s a link that will allow you to take a look at this in action —X2V grabs the hCard embedded at Web Directions, converts it to a vCard, and allows you to download it and open it in your address book.

But recently, Brian’s gone one better with a tool to create Google Maps mashups from hCards containing geodata. This example locates the hCard at, which contains geodata—the longitude and latitude for the location of the venue of this event. The geodata is then converted to Google Maps’ own XML data format, KML, and is then sent to Google Maps, which displays the location and its name. It’s a mashup without any need for Google’s APIs, and just a hint of the kind of thing people will be doing with open microformatted data.

So, what are you waiting for?

The network effect tells us that the value of a technology increases the more it is used. Microformats are rapidly experiencing the benefits of this effect. Innovative publishers are publishing microformats, while innovative developers have embraced microformats to help build new types of online services. These innovators have taken the plunge, demonstrating the practical value and the promise of microformats right now.

Even if you aren’t sure about developing with microformats quite yet, why not grab the Tails extension for Firefox, or the FlockTails extension for the Flock browser? You’ll be able to see which sites you visit are making use of hCard, hCalendar, or hReview. After Tails/FlockTails is installed, take a look at one of the reviews at Cork’d, or browse some sites at Yahoo! Tech. The new microfomats logo in the status bar at the bottom of your browser window will light up when a page contains microformatted content. Click the logo to get details of all the microformat items on the page.

Whether you are a web developer, content publisher, or service developer, you’ll be in good company if you consider how the content you publish, the applications you develop, or the services you provide could benefit from utilizing microformats. Looking for a cool new project? Why not aggregate restaurant, movie, book, or other reviews using Edgeio’s model? I’ll happily sit on your company’s advisory board.

Microformats have come of age. So, what are you waiting for?

More reading and resources

  1.—the home of microformats
  2. Microformatique unofficial microformats blog
  3. Introduction to Microformats by Brian Suda, O’Reilly ShortCuts series
  4. Microformats cheat sheet Brian Suda

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John Allsopp is the head developer of Style Master, the leading cross-platform CSS editor, and founder of Westciv, an Australian web software development and training company. Westciv provides some of the most widely read and respected CSS resources and tutorials on the web. One of the earliest members of the Web Standards Project, he’s also cofounder of the upcoming Web Directions Conference in Vancouver, BC.