1. Back in my day...
Waaay back in the 1900s as I approached graduation from Penn State, I was constantly interviewing for IT-related jobs. Before every interview I would go to the company's web site and that was the extent of the Internet research I'd do on my potential employers. Oh how far we've come! Now, I can literally search for the exact person who will be my boss and potentially uncover everything from EEOC complaints to discrimination lawsuits to specific allegations of abusiveness.
2. Public Shaming
Employment discrimination/harassment may carry a hefty price tag: litigation costs, potential liability (including attorneys' fees), not to mention the havoc of a toxic work environment. Now, to top it all off, the Internet provides for public shaming. Individual claims are rarely deemed newsworthy, but the Internet allows anyone to uncover the information with a quick web search. I'll also note that as societal attitudes toward discrimination have evolved there is now likely more shame involved in publication of the allegations than in the past.
I've had a number of bosses throughout my career and I can honestly say that each of them was "good." I think I've been lucky in that respect. But I suspect a number of people will read the Worst Bosses list and think, "and I thought my boss was bad!" Either way, the list may provide some perspective for your current situation.