One of the big issues with HTML has always been the limited support for different fonts, especially across browser and across platforms. SIFR is a well-known technique to replace HTML text with Flash fonts on the fly -- see the SIFR main page for more info. The text remains selectable and linkable, and the underlying HTML tags (h1, h2, etc.) are still fully accessible and indexed by search engines. See Typophile for a great, Drupal-powered example of this.
Up until now, integrating the scripts required has meant building it once and putting all the code directly into your theme. With this module, any Drupal user will be able to select which fonts (aka typography for the design nerds) to use, control which HTML paths (e.g. h1.title, .block-title, etc.) should be replaced, upload your SWF font files, and everything else to make it a seamless experience. Future versions may even allow the direct uploading of font files which will be converted server-side to SWF directly.