I do it sometimes while I'm out at sea. It passes the time when I'm bored during my off watch. Not much for sitting in front of a television or computer. I'm on this site for the same reason, simply to pass time now and then.
I'd be wary of the electronic cigarettes. Here in the states about 2 months ago, one blew up while a guy was using it. Blew his teeth out and part of his tongue as well. It also caught the room on fire. They say it was a faulty battery.
I think it sucks. Then again, I Don't like Facebook at all anyway. It never ceases to amaze me the amount of personal stuff people are willing to put out there for the whole world to see.
RE: mistakes
Because the cost for that knowledge can be very high.