As Wikipedia has become more prominent and as the community involved in creating Wikipedia has become larger, problems like harassment, intimidation, threats, extortion, coercion, stalking and vengeance have started to surface.
Wikipedia and the Wikimedia Foundation have very few resources to devote to this kind of problem, but there are probably some simple things that do not cost very much that could help a lot. I have made a list of suggestions off the top of my head for how to deal with harassment and intimidation problems. Some of these might actually be worth trying. If everyone made similar lists, and we started discussing them, we might actually come up with a few worthwhile ideas to try to improve our current situation.
One of the things that must be addressed initially is defining what is meant by harassment. We should not include trivial examples of bad or mischevious behavior, which include statements like "Tom's mother has a big nose", in the same category as threatening and disturbing statements like "Tom, I am flying into Cleveland next week and I know where your mother lives, so I am going to pay her a visit, rape her and kill her and you can't stop me".
By setting too low a threshold for inclusion of behavior into the harassment category, which might be addressed by a special harassment policy, we dilute our effectiveness and overcommit our very limited resources. Also, we create a situation where no one respects our policies. The somewhat dubious recent efforts to impose ever more stringent standards for CIVIL behavior can start to appear ridiculous. For example, it was being regularly claimed that edit summaries including words like "silly" were a violation of CIVIL. Some even claimed it is uncivil to suggest that the Klu Klux Klan is a racist organization. Obviously, as the definition of "uncivil" expands to cover more and more cases, communication is impaired and the very concept starts to lose meaning.
However, the threshold for harassment should not be too high either. Coercive statements like "If you don't do X for me, I will do Y to you" create a less- than-pleasant environment. Assertions that it is the "right" of a "wronged" editor to seek vengeance can also be problematic. For example, this reasoning leads to statements like "Since you voted against Z for RfA six months ago, I am going to do bad things to you now". Obviously, these kinds of statements can create a bad atmosphere and lead to further problems.
One of the frequently-asserted reasons for cracking down on CIVIL violations is that uncivil comments and personal attacks lead to an unpleasant editing environment on Wikipedia. If stating that someone's argument is "amazingly" incorrect is uncivil and sanctionable, or stating that someone is involved in "self promotion" is judged to be sanctionable , then surely coercive statements and statements meant to intimidate like "I am going to attack you out of a desire for revenge" should be similarly sanctionable. Also, if we do not respond to these sorts of statements with any sense of urgency, a general impression develops that any kind of threat or vengeance for some perceived "wrong" is permissable. And once these kinds of behaviors are allowed, it is tantamount to encouraging them, and they will escalate.