Well specifically, he's the maintainer of INTERCAL[1], an esoteric/outright evil programming language that, from his request (if I'm not being too credulous; it's at least plausible), Knuth must find amusing. Of course he's not a Computer Scientist on the level of Knuth, but my awareness of him, at least, is as an important cultural figure in computer-aware politics (from back when this was a distinguishable perspective), and a curator of a significant chunk of the culture of hackers from a formative era, which they were both a part of, that might otherwise be left abandoned. I'd hesitate to frame him as appreciable as a philosopher to Knuth's scientist, because he's a hacker who's also made real contributions to code that is still in use today; but his essay 'The Cathedral and the Bazaar'[2], at the very least, was an important text in laying down, and communicating to those who may not have previously understood, an open source philosophy that we take as a given position today.
I dunno, I'm just surprised to see the lack of recognition apparent in a thread on Hacker News about someone who I think of as a notably important figure, a hacker elder. I'm not from that era, maybe I just read too much Slashdot back in the day.
[1] http://en.wikipedia.org/wiki/INTERCAL
[2] http://www.catb.org/~esr/writings/cathedral-bazaar/cathedral...
