[mmastrac]

The fonts themselves are cached for a "long time", but the CSS that links the font to a @font-face declaration expires far more frequently (ie: less than a day).

In my testing on slow connections, serving fonts from Google's site generally results in missing text on iOS devices and Safari if the cache is cold.

By inlining a woff font in the stylesheet you take a bigger hit on the first request to your site (~110kB for my site with three web fonts), but you never see the missing text. Because I'm inlining this in my CSS, I can ensure that it's strongly cached for return visitors and they pay this only once.

It's all a tradeoff that you have to judge for yourself: "What are the chances that a given user has a specific font that you've decided to use cached?" vs "What experience do you want the user to have on a cold cache".

[hubot]

given that most browsers already support woff, i may go with your approach :).