It still doesn't matter much (it helps with price discovery, as HFT participants provide smaller spreads than traditional market makers, which helps with liquidity, and the volatility they add in case they withdraw from the market doesn't seem problematic, because when they withdraw they do so in order to prevent trading in very non-understood regimes, so they don't trade in chaos, wow, blame them, and/or ban them, but you lose the much greater benefit too).
And yes, it's different, because when HN was new its comments were a lot more precise and fact-based, now it's full of dogmatic luddites.
And yes, it's different, because when HN was new its comments were a lot more precise and fact-based, now it's full of dogmatic luddites.