"Font embedding" is coming back to the web! The latest build of WebKit (used by Safari) has it, Opera is expected to follow. But the way they use it is by just linking a regular font file, which has to be placed somewhere on the internet, so everyone can download it.
Of course that doesn't go well with commercial fonts.
So I set up a Proof of Concept to show a way to secure* a font used with the font-face command. Just download the latest version of Safari and open this page:
http://www.fonts.info/webfonts/
You should see two "embedded" fonts. The first is protected*, the second is not. Feel free to try to download Kaffeesatz. I won't explain how the protection works, but it uses several layers of protection. It is set up in a way, where the font would reside on the foundry's server and a remote, licensed website can use the font by adding a little snippet of code to its template.

* So it's absolutely safe? No! Everything you see in your browser window was already downloaded to you machine. There is no real protection for anything that is on the web.