An alternative way of looking at web fonts sees it as only another method of ‘embedding’ the font in a document, like is done with PDFs. The OFL-FAQ defines embedding as “…inclusion of the font in a document or file in a way that makes extraction (and redistribution) difficult or clearly discouraged. In many cases the names of embedded fonts might also not be obvious to those reading the document, the font data format might be altered, and only a subset of the font - only the glyphs required for the text - might be included.” (OFL-FAQ 1.11) When the modification of the font is clearly only part of the embedding process - such as in a PDF - RFNs are allowed.
So can web fonts be interpreted as embedding? There may even be similar technical processes as are used for PDFs - removing glyphs that are not needed, changing the font format itself, leaving out metadata.
However, there a few ways in which web font mechanisms differ from traditional embedding:
- Web fonts are normally more complete than document-specific subsets as is common with PDFs (except in the case of Dynamic Subsetting).
- The same web font can be used by many pages, whereas embedded fonts are integrated into each individual document.
- Most web fonts are not even delivered from the same server as the HTML/CSS, and one font may be served to thousands of pages.
- Web fonts remain separate resources or files, loaded separately from the HTML pages.
- The potential ease by which the general public could download and convert some web fonts into something usable on the desktop has led companies to go to great lengths to obfuscate some web fonts.
- There is even a Firefox extension (although not updated for current versions) that will download web fonts used on a page: http://code.google.com/p/web-font-downloader/
- Unlike some PDFs, for example, the content of a web page is normally still present and readable to the user even if the font is not working.
The main points here are that web fonts are not an integrated part of the document itself, and despite vendor efforts to minimise conversion of web fonts for desktop use such efforts will likely remain desirable, especially for OFL-licensed fonts. There is little reason to discourage this for OFL fonts and some authors may want to encourage it.
In conclusion, web fonts cannot be considered a simple alternative form of document embedding.
This mean I must include ofl text or url?
I think you are making this too complicated. From your earlier question it sounds like you want to include web fonts in themes. If you distribute the font with or inside your theme, for example as TTF or WOFF or SVG files, then you must include the OFL.txt and should include the OFL-FAQ.txt and FONTLOG.txt. That is typically done by including them in the same folder where you put the web font files.
The link and license do not need to be on your theme template pages, and web sites using your theme do not have to show the license.
If your theme only uses of the font by linking to font services (such as Google Fonts, Adobe TypeKit), then you do not need to include the license.
In any case, web sites that use OFL fonts do not need to show the license on pages.
Hope that helps,
Thank you very much!