In his book, The Wisdom of Crowds, James Suroweicki says that to effectively harness the collective intelligence of a crowd, there needs to be the right balance between
Surowiecki's observations lead directly to two information design principles:
Consider a Web designer that embeds a family name in an HTML <li> element, e.g.,
<li>Costello</li>
A second Web designer embeds a family name in an HTML <div> element, e.g.,
<div>Novak</div>
A third Web designer embeds a family name in an XML element, e.g.,
<informant>Smith</informant>
A fourth Web designer embeds a family name in an XML element, e.g.,
<pilot>Johnson</pilot>
A fifth Web designer embeds a family name in an RSS element, e.g.,
<managingEditor>Parker</managingEditor>
Each of these Web designers are expressing the family name information in a way that is resolutely specific and local, i.e., in a way that is appropriate for his/her specific needs and requirements
However, the information is not globally and collectively useful, i.e., without a-priori knowledge a general Web tool cannot ascertain that the information within the elements represents a person's family name. That's where Microformats come into the picture.
Add the hCard "family-name" subproperty to each local expression:
<li class="family-name">Costello</li> <div class="family-name">Novak<div> <informant class="family-name">Smith</informant> <pilot class="family-name">Johnson</pilot> <managingEditor class="family-name">Parker</managingEditor>
Now the information is resolutely specific and local; simultaneously it is globally and collectively useful.
Consider a product manufacturer that releases a list of their products "by family" and marks up their content with the class "family-name", how is it distinguished from the hCard Microformat family-name subproproperty?
There are two ways:
First, the family-name is embedded within an element with class="vcard", e.g.,
<div class="vcard"> ... <div class="family-name">Novak</div> ... </div>
Thus, the context can identify that family-name refers to the hCard family-name subproperty, and not some other family-name.
Second, the hCard profile URL indicates that "within this document is an hCard Microformat", e.g.,
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head profile="http://www.w3.org/2006/03/hcard"> ... </head> <body> <div class="vcard"> ... <div class="family-name">Novak</div> ... </div> </body> </html>
Now there are two indications that family-name represents an hCard family-name subproperty.