Last week I added WOFF support to Chromium. It's currently on trunk and hopefully will be included in a dev channel release by the end of this week.
WOFF is a repackaging of the old sfnt/TrueType/OpenType format. Conceptually it's just a gzipped TTF file with optional sections for a chunk of XML and a chunk of 'private data'. Since TrueType is a table based format already, those two optional sections could have been included as tables. And since we have gzip as a transport encoding in all reasonable HTTP servers, that's a little pointless too.
So, technically, there's no need to WOFF to exist at all. It's all politics. The type foundries didn't want a format which people could use on their computers. Of course, it's trivial to convert them (Chromium does it internally), but if it gets the foundries and Microsoft on board, then it's worthwhile.
But I do worry that WOFF will actually make web sites look worse. All the samples and examples that I've seen (even the nice ones) are terribly hinted. I assume that this is because the people doing them are using Macs, which traditionally don't hint anyway. But I prefer strong hinting and, in this mode, the free fonts look blotchy. They just haven't had the time and effort put in that my system fonts (often msttcorefonts) have had.
So I can always tell when a site is using @font-face, because it looks bad. Which is rather a shame given the intention.