Physicality and mentality are largely affected when rape or sexual harassment occurs in real life, but the lines do tend to blur when it comes to a virtual medium. While it's true that the mental aspect can come into play with such media, it is not necessarily a certainty. I find that how affected a person is deals with how attached they are to the virtual form in which they are being harassed. A person who has a phone constantly glued to their ear might (though it's not a certainty) find it more difficult to hang up when such harassment occurs than someone who uses one less frequently. The more comfortable one is a with a phone, the more it can be hard to pull away...or so I've heard...I'm one of the few out there who could care less about using the telephone. Those dependent on e-mail might take things to heart much more seriously than those who aren't. A case in point would be all of those chain e-mails going around. I like e-mail as much as the next person, but I'm not overly dependent on it for communication, so when I see a chain letter in my inbox (or one from a person I know would send me such an e-mail,) it gets automatically deleted. Though there are those who just can't resist the urge to send it to everyone in their e-mail address book. Getting them and feeling the need to keep them up can be true harassment. Now, I know that example isn't based off of sexual harassment, but when it comes to the virtual world many forms of harassment can be abstracted to fit under the umbrella.
And MOOs/MUDs and other chat clients...it really all depends on how attached, how addicted, a person is to the persona they play and whether it's casual interaction or harcore role playing. As with those on Lambdamoo, most seem to truly be into the experience they are having there, and even Dibbell claims that he has been jaded by all of his time spent there so his account might not be entirely unbiased. In that case, they would take to heart the rape of their character much more seriously than one who goes into a chat room every once in a while. Much like Dibbell, I too roleplay as a doctor from an almost forgotten TV show, and if anything should happen to my character, it would indeed reflect on my mentality. Of course it's not real, but for this I am him and he is me, so essentially, even if it is a persona, I'm putting myself in there. But should I go elsewhere, someplace I frequent less often, any form of harassment would roll right off my back.