On April 8, 2010, Mozilla, Opera and Microsoft submitted the Web Open Font Format (WOFF) File Format 1.0 specification to W3C. “This document specifies WOFF font format designed to provide lightweight, easy-to-implement compression of font data, suitable for use in conjunction with @font-face CSS declaration. Any TrueType/OpenType/Open Font Format file can be losslessly converted to WOFF for Web use (subject to licensing of the font data); once decoded by a user agent, the WOFF font will display identically to original desktop font from which it was created. WOFF format also allows additional metadata to be attached to file; this can be used by font designers or vendors to include licensing or other information, beyond that present in original font. Such metadata doesn’t affect rendering of font in any way, but may be displayed to user on request. WOFF format isn’t expected to replace other formats such as TrueType/OpenType/Open Font Format or SVG fonts, but provides an alternative solution for use cases where these formats may be less performant, or where licensing considerations make their use less acceptable,” reads the abstract.
More info: WOFF File Format 1.0