The @font-face command, which allows users to embed fonts inside of a website, will change the face of web design as we know it. I've been hearing about this idea for years, but it was only yesterday when I saw it in use at this example site (articles at Mojo Type & Slate). Only Firefox 3.5 and the latest release of Safari are displaying it correctly so far.
Designers are no longer limited to preinstalled fonts on the user's computer. The links go into the legal spats that results with open source fonts and free font distribution. What eventually is needed is a way to distribute fonts that includes a limited closed version of the font files, but that would take a complete rewrite of how fonts are dealt with so that'll take years to become widespread. Alternatively, making certain fonts completely opensource would also solve the problem, but we'd fall into the same trap of still only having access to lousy non-professional fonts (though with a choice from 1000's rather then dozens.)
The @font-face is as fundemental of a change to the web as the ability to include pictures in a site and it will be fascinating to see how designers start using it. It's the difference between choosing from 256 colors (as web designers used to have to do) and millions (as they can now). Admittedly there's a two year lag on acceptance of technology like this, but it's an exciting new frontier.
(image by wilhei55 )