It's nice to sit down at a table to play a board game. You get some real human interaction that is missing from, say, television. But when it's time for dinner, you have to end the game. Or the peices get distributed -- under the sofa, behind the dresser, into a baby's digestive tract.
These problems go away when you play on a PC. No losing virtual chess peices. Go works well on the computer, too. Dominoes doesn't as well, since you can't hide your peices from your opponent, but having two PCs can do the trick.
But I'm still trying to figure how to get an online version of Twister.