No, it will not affect you. The above post is mostly correct, but it's misleading because it's from the perspective of a trader trying to make short term profits. But most of us are considered investors, we periodically buy/sell low volume of liquid ETF/funds/stocks and hold our positions for years. Market makers do collect a tiny premium for every trade, but it's irrelevant for the time horizon that investors are concerned with.
Since this is hackernews, I'd imagine there are a decent amount of people with low float tech stocks. Those things can be impressively squirrely. I've moved a billion dollar company 5% with a $100,000 order by being a klutz.
Granted, these situations are usually in times of market stress, but these are times when for better or for worse people do need to raise personal cash on occasion.
