When we boarded our first cruise ship there was no Facebook, no Twitter, no Internet message boards. In fact there was no Internet as we now know it.
At the time, it actually didn't occur to us that we would ever want to "friend" a fellow passenger ahead of time, send a "tweet" out to potential cruise mates, or join a "roll call" in order to have a ready-made social circle on our cruise vacation.
Back then we didn't feel it was necessary to have a group of acquaintances aboard ship in order to feel comfortable on a cruise. It still isn't necessary and you can still do your "networking" on board as we did—and still do.
Ultimately, you have to decide whether social networking—online or on board—is right for you. You be the judge. Cruise Diva looks at Cruises, the Social Network Way to Travel.