This is sad news, but less sad than a funeral and cremation would have been. I met Hal in the 1990s via the cypherpunks list, where a young Julian Assange was also hanging out. Hal went on to work for PGP Corp. in its glory days, and was involved in the early stages of Bitcoin as well. He is (not was!) the consummate cypherpunk and extropian.
A lot of those discussions have been lost to time, but here's a note from Hal that I posted to Politech in 1999 where he warned against building surveillance backdoors in Internet standards:
http://seclists.org/politech/1999/Oct/24
"If the IETF sets the precedent of acceding to the wishes of countries like the US and Europe, it may find itself forced to similarly honor the desires of less open societies."
And here's Hal responding to one of my Wired articles by pointing out the absurdity of the MPAA's claims against Napster:
http://extropians.weidai.com/extropians.1Q01/3833.html
"Looking at it over the history of Napster the amount would have to run
well into the quadrillions. Surely this would be the largest legal
claim in history! I wonder if the record companies can present this
figure with a straight face."
I'll miss Hal. At least there's a very slim, but non-zero, chance he'll log back on again.