Most people have a tenuous knowledge at best about what stocks are or the ecosystem behind the stock market, how to analyze stocks, or what the rules of trading are (I managed to break one when I briefly thought I could daytrade from Sharebuilder years and years ago and got suspended from trading for a few days).
They don't understand it much more than most people understand Bitcoin. Not really. It's all 'buy X and hope the number goes up!', where X is a mutual fund or random company, just like with Bitcoin/Altcoins.
Most people will at least know that a share is a tiny fraction of a company, and why it has value. Bitcoin is more of a black box (to many), and thus more prone to hype (it's far easier to make grandiose claims about the future of a currency than it is to pretend a company will grow at nearly the same rate).
They don't understand it much more than most people understand Bitcoin. Not really. It's all 'buy X and hope the number goes up!', where X is a mutual fund or random company, just like with Bitcoin/Altcoins.