The model that has worked for us in the bay area is to build a community around the games, typically a league. We now have six leagues in the greater bay area from Sacramento to San Jose.
I used to run $5 tournaments every two weeks on Tuesday nights at a bar. They were competitive, of course, but as much about the socializing side of pinball.
Over the course of about six months it made the place a destination. It went from four games to six, including a MM and a new ACDC. The bar owner would give me coupons for a free drink or appetizer, which I raffled off and gave to first timers (they broke even no matter how good/bad they played). The operator is a friend of mine and kept the games in great shape.
Everyone wins - the bar and operator get business, we got great games and an opportunity to hang out with other pinheads over some drinks, earn some wppr points and make a few bucks if we won.
Before long, I would go to play a few games after work and there would be four or five people already there. Players started telling other players and the attendance continued to increase. We got 47 players for our ACDC launch party on a Tuesday. Another time we got 40 players after the local indie paper published a blurb about my tournaments.
This isn't the only path to success but it seems to do well around here.
Socializing through web sites and facebook is fine and all, but people also want that face to face interaction. They want to put up a score and get cheered by their fellow players or talk tech or chat up the girls. Personally, I don't feel that just putting games in a space is enough anymore. People have too many entertainment options, and lets face it, pinball is not an easy game to learn. But if you engage people and turn the whole thing into an event, then they're going to have fun whether they win or lose. When they see how good players play, they learn and get better. If they make a few friends over the course of the evening, they have yet another reason to come back next time.