Firefox shows simply a blank page (0 bytes), curl says "Empty reply from server" and Google Chrome notes "Error 324 (net::ERR_EMPTY_RESPONSE): Unknown error."
My IP address can be viewed at http://yfrog.com/el64282782g. I have maintained only this account, which is still available and I have never posted anything controversial. In fact, I haven't submitted or commented on anything in the last three weeks or so at all. I ought it highly unlikely that my family with whom I share this IP would be interested in Hacker News so that can't be it either.
Can PG or someone else please check and see if my address is in fact banned or if it is a problem at the client's side.
Thanks, Daniel
P.S. I know recall having recently installed this userscript:
http://github.com/brainkarma/hnreputation/tree/master
Might that have triggered an automatic anti-dos/anti-scraping ban?