The WOFF format came from a collaboration between font designers Erik Van Blokland, Tal Leming and Jonathan Kew from Mozilla. WOFF stands for Web Open Font Format, which is a simple compressed file format for fonts, designed primarily for use on the web. According to a report written by these three people, WOFF File Format (draft of 2009-10-23,) the WOFF format is directly based on the table-based sfnt structure used in TrueType, OpenType and Open Font Format fonts, which are collectively referred to as sfnt-based fonts. A WOFF font file is simply a repackaged version of a sfnt-based font in compressed form. The format also allows font metadata and private-use data to be included separately from the font data. WOFF encoding tools convert an existing sfnt-based font into a WOFF formatted file, and user agents restore the original sfnt-based font data for use with a webpage. WOFF is designed so that the structure and contents of decompressed font data should match that of the original font file.
Advantages of WOFF:
According to an article written by Christopher Blizzard in 2009, Web Open Font Format for Firefox 3.6 (http://hacks.mozilla.org/2009/10/woff/):
1. Compared to TrueType or OpenType, WOFF is compressed, which means that you will typically see much smaller download sizes compared with raw TrueType or OpenType fonts.
2. It contains information that allows you to see where the font came from – without DRM or labeling for a specific domain – which means it has support from a large number of font creators and font foundries.
Other advantages of WOFF from the website of Mozilla Developer
(https://developer.mozilla.org/en/About_WOFF )
3. The font data is compressed, so sites using WOFF will use less bandwidth and will load faster than if they used equivalent uncompressed TrueType or OpenType files.
4. Many font vendors that are unwilling to license their TrueType or OpenType format fonts for use on the web will license WOFF format fonts. This improves availability of fonts to site designers.
5. Both proprietary and free-software browser vendors like the WOFF format, so it has the potential of becoming a truly universal, interoperable font format for the web, unlike other current font formats.
6. You can also have Better Typography for the Web (OpenType features such as contextual forms and old style figures)
7. More languages can be represented in the website
Disadvantages of WOFF:
It is still in the process of developing to become a universal format, so websites using WOFF have a compatible problem. Only the latest versions of IE, Firefox and Google Chrome support WOFF (IE9, Firefox 3.6 and Google Chrome 5.0). Safari has not yet supported WOFF. Here is an example of how a website using WOFF appears in Safari and Firefox:
Website: http://ie.microsoft.com/testdrive/Graphics/WebFonts/Default.html
Safari:
The titles of each article and the text even overlap with one another. The font of “Imperial Identity System Unearthed” cannot be loaded so Safari used the default or truetype font for it.
Firefox:
Websites that apply WOFF:
http://ie.microsoft.com/testdrive/Graphics/WebFonts/Default.html
WOFF is put under the heading & style tag
Browsers that support the WOFF format will download the WOFF file. Other browsers that support @font-face but don’t yet support the WOFF format will use the TrueType version.
http://ie.microsoft.com/testdrive/Graphics/MoreWebFonts/Default.html
Similarly, WOFF is put under the heading tag