HN is interesting because of the community and Y combinator's backing. The software behind it is laughably crude compared to other web forums. It could easily be replicated in any number of other languages, with better results. Maybe we'd even see the last of those "link expired" errors?
Surely you know the history to which the previous poster is referring? YC exists because pg and others build a company in Lisp and sold it for millions. They were a small team so they chose Lisp exactly because it helped them stay nimble.
They chose Lisp because they were comfortable with it - nimble is a social trait, not a language feature.
It's not like Lisp automatically makes everything successful - the market-trailing HN performance and UI iteration times are a strong argument that technical factors frequently do not determine success.