Got me started thinking about this (again):
I had a housemate once who would become completely obsessed with a new video game and play it continuously until he had completed all the levels. It took a couple months for him to master Grand Theft Auto. He took me for a ride in it. Our virtual reality was shared in living and breathing space, and he was not a lost cause. I don't think. I hope not.
I have a friend who lives a good fraction of her life in second life. She is married in this life and has a significant other in second life. Her 2nd life SO is known to her and her husband. He has a wife and kids. They visit together, eat icecream, break ankles, breathe the same air. Second life has merged with first life.
I have a sister whose occupation is building things for the second world. That is, she obtains or develops images and sounds that she can sell for virtual money. Her reality is beyond my comprehension, except that when she is there beside me she is just as solidly herself as she has ever been, with a sharpened wit.
I have a boyfriend who barely exists on the internet. I told him how many fb friends I have now and he laughed at me. I think he is afraid that I will go where my sister went, or my friend. He likes to exercise and play his guitar and garden and read. Doing all those other things sounds far better than this. I'm outta here.