As best as I can tell, it means something like "using the generally available levers of social shame and guilt to dissuade someone from doing something, or if they have already done the bad thing, then requiring them to explain their behavior in a satisfactory way and make a public commitment to avoid doing it again."

And it requires that you be in a position of power - otherwise it's just heckling, which isn't likely to have any real impact. In this case it'd be having the ability to impose fines, or discipline corporate officers, etc.

I wouldn't think of bad press is "just heckling." A company's reputation can be worth billions in sales.

It's true that many boycotts fizzle out, though.