What that means is web designers can get easy access to creative fonts without having to spend the time preparing images or Flash files to render them, ideally resulting in time and cost savings in the design stage. It should also provide a more lightweight experience for your web server, because it won't have to serve up the comparatively heavyweight image or Flash files to render a variety of design-quality fonts.
It also means all that text will be searchable and indexable by Google instead of locked up in an image or Flash file. That means a search engine optimization boost could be in store for sites that opt for Typekit, as well as better accessibility which makes for improved user experience.
The caveat attached to all the benefits is that only browsers that support the CSS @font-face rule will be able to serve Typekit's fonts. That means support is limited to Firefox 3.5 and up, Safari 3.4 and up, and Internet Explorer version 5 and up. That could rule out its adoption by webmasters whose sites must support older and legacy browsers.
Typekit is employing a freemium business model, with a non-expiring "Trial" tier you can access for free with certain limitations (5 GB monthly bandwidth, smaller font selection, only 1 site and 2 fonts per site supported, and a Typekit badge required). Personal plans start at $24.99 per year with two more tiers above that and negotiable enterprise pricing available as well.