Some time in 2009, Firefox and Opera began shipping @font-face support with the former behavior: text would render with fallback fonts until downloadable font resources became available. But this choice frustrated many users (see the Firefox bug report) and was quickly dubbed FOUT, the Flash of Unstyled Text . Articles were written about fighting the @font-face FOUT. It wasn’t long before most browsers were hiding text while fonts downloaded. Unfortunately, the main issue with @font-face now is what many wanted to avoid years ago: the FOIT, or Flash of Invisible Text.
Source: The @font-face dilemma | Viget