Adobe has released their first-ever open source typeface, Source Sans Pro.
The design of Source Sans is based on fonts like Franklin Gothic and News Gothic. It is intended to be appropriate for both small UI labels and longer passages of text.
So what does it mean for a font to be "open source"? It means that in addition to being able to download the fonts for free and use them as is, you can also download the source code and edit it with software like the Adobe Font Development Kit for OpenType (under the terms of the SIL Open Font License).
In fact, the design of the glyphs has already been a community effort, as user feedback lead to the lowercase l being reshaped to be more easily distinguished from the uppercase I.
And the team effort will continue, as type designer Paul D. Hunt mentioned in his announcement post at the Adobe Type Team blog, "In addition to making these files available as a learning resource, we are eager that this project will become an undertaking in which we can collaborate with others in the design community." Additional features such as Greek and Cyrillic support, and a monowidth version of the font are currently in development.
Of course, if all you’re interested in is a high-quality free font from Adobe, you can ignore all the open source code and simply download the fonts (in OTF or TTF format) for use in any application. The Source Sans family includes six weights, ranging from ExtraLight to Black, in both upright and italic styles. And there’s also PDF of glyph specimens for your perusal.