While I agree with everyone else that "rape" is seemingly impossible online.
I do believe that a person can be emotionally, and mentally traumatized through the actions and words of others.
People join groups, forums, chats, etc... to meet with others who share similar likes and dislikes online.
Sometimes they like to keep thier anonymity, and sometimes they can create a whole new personae they would not otherwise be able to be or show in real life.
The online community can be a great place to meet new people, share your thoughts, and make new friends.
But of course there is always a downside to things as well. I am sure that there are adults out there who strive to belong in a place where in real life they are unsuccessful.
This is probably where the fine line of "virtual rape" would come into play.
A person who would do anything to be accepted, wanted, or needed, could also convey a newbie sort of eagerness, that a sexual online predator could possibly pick up on.
I have heard many stories of women who are eager to please and be accepted, be taken advantage of online, and the emotional scars can last a very long time.
Since we now have cyber bullying, I am guessing that a person taken advantage of in any sexual form on line, would be considered a virtual rape.
And since cyber bullying can now harbour criminal charges, I am sure that given time there will eventually be one for virtual rape as well.