Arc90 was a software and design firm; its blog covered the Readability reading tool and web design.
HN links it for the history of Readability, including how Safari 5's Reader drew on it, plus ports to other languages.
It's interesting to hear from type designer, certainly not a voice that is heard often enough, at least not in the web developer community. His concern that "someone can take one of our fonts, put it in a freely accessible directory on their server, that’s a violation of most of our license agreements" is nothing new. Håkon's "free font" technique does not introduce this problem, nor does it make it any worse in my opinion.
As a side note, I find it incredibly ironic how difficult it is to read that web page due to the "design" choices made. Thank god for readability: http://blog.arc90.com/2009/04/readability_updated_with_some.php
Actually, if you look in the Safari 5 credits, you'll find reference to the original Readability script. Here's the official Readability (arc90) blog post about it: http://blog.arc90.com/2010/06/10/why-we-built-readability/
Readability has been ported to Python and Php: http://blog.arc90.com/2009/06/20/readability-now-available-in-three-delicious-flavors/ There is also a C# port here: http://code.google.com/p/nreadability/
Their blog says "we couldn’t be happier that Apple has chosen to leverage our own Readability as a native feature in the Safari browser."
http://blog.arc90.com/2010/06/10/why-we-built-readability/
http://blog.arc90.com/2010/06/07/safari-5-another-step-towards-better-reading-on-the-web/
(last paragraph links to: http://twitter.com/chrisdary/status/15672452287)
For some extra reference:
http://lab.arc90.com/2012/09/18/sassme
http://blog.arc90.com/2012/09/18/announcing-sassme