The Web Open Font Format, already backed by Mozilla and many type foundries was accepted by the World Wide Web Consortium yesterday, marking the first stage in its standardization. The submission included a surprising new sponsor: Microsoft.

Font distribution is a hairy issue. The fundamental problem is that using a particular font within a Web browser requires that font to be available on each and every machine that will visit the page. The font choice obviously has a substantial impact on the appearance of a page, but because the font must be available on each visiting machine, designers are generally forced to stick with the small number of fonts that are widely installed and distributed; the result is that we see a small selection of fonts (such as Arial and Times New Roman) used over and over again. Microsoft has in the past shipped a pack of fonts, the Core Fonts for the Web to provide a few common options that designers could rely on, but the company stopped distributing them in 2002 after consistent EULA violations.

The result is that designers have generally had two choices: using images to represent text (which is inconvenient to maintain, invisible to search engines, and inaccessible to end-users), or stick with one of the handful of widely available fonts.

Distributing the font files themselves is normally not an option. Fonts are often expensive to license, and those license terms prevent arbitrary redistribution, just as they do for most commercial software. However, many fonts allow some kind of embedding to be performed. This is commonly used with PDFs and similar document formats; generally, a cut-down version of the font is generated (so that it contains only the characters required for a given document), and this cut-down font is embedded into the document. The combination of trimming down the font (so that it doesn't contain the full range of characters) and embedding it (so it can't easily be extracted) is generally sufficient protection.

The Web font initiative strives to provide this same capability for webpages. CSS has long allowed font files to be specified for use in a page, but there has never been a widely accepted file format for fonts used in this way. To be a good solution, the format has to support features like generation of subsets, compression to reduce sizes, and needs to incorporate the necessary licensing information to restrict usage. It also needs to be compatible with existing font formats, so that existing character outlines can be easily adapted to the new format.

The WOFF standard achieves all this. It allows enough restrictions and licensing information that the type foundries who create the fonts are generally happy with it, it offers enough capabilities that it's useful to Web designers and browser authors, and it leverages existing font technology for the actual character descriptions, so it works neatly with existing font files.

WOFF itself is a fusion of two previous efforts to solve this problem: ZOT, originally devised by Mozilla, and .webfont, created by typographers. There have also been other efforts in this direction in the past; Internet Explorer supports a Microsoft invention called Embedded OpenType (a subsetted, compressed variant of the OpenType specification), Safari and Mozilla support direct use of OpenType fonts, and SVG can be used to create fonts too. The industry has lacked any kind of consensus and standardization.

That's set to change with WOFF. With the submission to W3C now accepted, the recently chartered WebFonts Working Group will work on refining the specification and developing it into a formal recommendation. Microsoft's support is particularly important. Internet Explorer still commands a substantial market share, so Microsoft support is essential if the feature is to be widely supported.

This decision also underlines the company's new commitment to Web standards; where once the company might have been expected to stick with its own solution, it's clear that now it wants to work with the rest of the industry rather than going it alone. That said, there's been no indication yet of whether WOFF support will be included in IE9. With the next browser version still likely to be some way off, the company has been reluctant to commit to support any particular specification (though it has confirmed that certain big ticket items like the HTML5 video tag will be included). We'll have to wait and see to find out just how serious support for WOFF really is.