XHTML: The X stands for "Extensible", and this kind of HTML works hand in hand with XML (eXtensible Markup Language) to enable people to create more customized tags with specific behaviors attached to each one.
In the early days of MySQL, you had to create your own PHP files (such as the one described on Kirupa.com) in order to parse all of the data out of those MySQL tables and into a well-formed XML document.
EasyPodder - Created for Windows and Linux, this is a one-stop shop for podcast production, generating RSS feeds (as .xml files), ID3 tags, and even providing an FTP tool for uploading your podcast.
With the advent of dynamically generated sites, a great deal of HTML has been replaced by more suitable languages such as eXtensible Markup Language (XML) and Cascading Style Sheets (CSS).
It provides animation control, database integration, a complete scripting language (called "ActionScript") and even integrates with many other web technologies such as XML and Quicktime.
AJAX, Flash, and other Web 2.0 Technologies: Depending on what your site needs, you may need to delve into database structures like MySQL or XML, or some of the newer technologies.
Cascading Style Sheets (CSS) is an Internet programming protocol that formats the appearance of various elements within a web page by assigning style values within the HTML or XML.
However, now web designers have a few valuable tools available called "feed generators" that will automatically generate an XML formatted RSS feed for your web page.
Videos would also include the format, episode number, etc. Since XML is eminently customizable, the content producer can include whatever they want in their RSS file.
You could create this XML file by hand, but that process can feel complicated and cumbersome, especially for anyone who doesn't have any programming knowledge.