It's amazing what you can find bouncing around the Internet. I stumbled across microformats while looking for something else. Microformats are a way of embedding semantic information on a Web page. They're designed to augment human-readable versions so software can easily and accurately extract the same information. Also, they're based on a small set of open data formats built upon existing and widely adopted standards.
Microformats are an implementation of the REST (Representational State Transfer) architectural style. REST is a method for sending domain-specific data over HTTP without using a messaging layer like the XML-based SOAP (Simple Object Access Protocol). Microformats are one way to implement the REST style by mixing metadata with HTML or XHTML.
A microformat like hCard defines a standard set of attributes. In this case, the information can be used to map data from another standard, vCard. A Web browser would display a sample hCard XHTML representation (Fig. 1) in a human-readable form (Fig. 2). The XHTML text is easy to parse using an XML parser because XHTML is XML.
The big difference between the microformat version and a comparable XML encoding is that the microformat can be displayed without an XSLT transformation file (Fig. 3). With XML data files, the machine gets preference. But with microformats, the human-readable form is augmented so software can extract useful information.
Microformats will be quite beneficial to developers who are creating Web interfaces to embedded devices. Most developers already have developed HTML or XHTML presentations. Microformats enable this approach to be augmented, allowing more sophisticated interaction with the system.
Web browsers can display microformat information, but enhancing the browser to recognize standard microformats like hCard will let users extract structured data, not just displayed text. Future browsers like Firefox 3 and Internet Explorer 8 will have microformat support.
Developers will be able to take advantage of the data encoded using microformats. This may be using embedded applications using tools like AJAX (see "Working Within The Framework") or applications that access an embedded device's Web services.
A great source is John Allsopp's book Microformats: Empowering Your Markup for Web 2.0, published by Apress (see ED Online 15617 for a full review).