Well, I'm not sure I agree that not much harassment goes on in more established companies, but you're absolutely right that at least they're more likely to have procedures in place for dealing with it.

This is why I'm astonished to see such strenuous effort go into confecting explanations why there might not really be a problem in startup culture. You've got young, inexperienced founders and a tendency to dispense with formal HR practises in favour of "cultural fit" - the ingredients are all there for horrible abuses of power, and yet when said abuses inevitably surface, there's an almost desperate effort to hand-wave them away as isolated incidents. It's bewildering, it really is.

Model View Culture have been publishing some superb work in this area, most relevantly in this article:

http://modelviewculture.com/pieces/hr-antipatterns-at-startu...