The Zend Developer Zone has a new post referencing one of the featured classes from the PHPClasses.org website - one that can create an automatic tag cloud for just about any site out there.
But how can you build a tag cloud for a site that did not have any kind of content tagging or categorization? This is a problem that can be solved by the Automatic Keyword Generator class written by Ver Pangonilo from the Philippines.
The ZDZ post includes an example of the class' usage - a pretty simple example of how it parses a string of data and, using a set of rules, parses through it to create the tags for the information.