Check out this piece on the Upper West Side community of 20-something single Modern Orthodox - the "Metrodox:"

"No matter where one grew up -- their background, their religiosity -- the Upper West Side has become the hub for the post-college single Jew," says Isaac Galena who, along with his twin brother Seth, run the Metrodox Web portal, bangitout.com. "Most Jewish communities, if not all, have a tendency to make Orthodox single people in their 20's feel like freaks. As if there is something seriously wrong with them since they aren't married by the age of 23. The Upper West Side serves as a community that embraces people in singlehood. It makes them feel as though they belong and serves almost as a fun support group and a stepping stone during this interim period."
As Galena will tell you, an interim period implies that eventually the Metrodox will find a mate, get married, and graduate to greener, probably more suburban, pastures.
So, what's the dating scene like? Picture a Jewish Melrose Place. With thousands of young Jews packed into the same neighborhood, Metrodox dating has become a phenomenon all to itself. Consider this: Jewish singles from all across America travel to the Upper West Side just to go on dates.
One out-of-state 28-year-old male who, for obvious reasons, wished to remain anonymous, told Jewsweek he traveled to New York 13 times in one year alone, and has gone out on more than 100 dates with Metrodox girls. Asked why he didn't just move there, he had this to say: "If I lived in the Upper West Side and saw hundred of available Modern Orthodox women at synagogue, I wouldn't even know where to begin. It would literally be overwhelming and I'm afraid, like many who live there, I would just get jaded."
If desired, a typical Metrodox male could go out with a different girl every night of the week -- for an entire year. There's an entire cottage industry around Web sites that cater to the Metrodox's dating needs including jewishcafe.com and frumster.com. And once somebody gets engaged, they can post pictures and mazal tovs online at Onlysimchas.com. Some Metrodox check the site twice a day.

I've always looked at the Upper West Side community as an ideal place for a short visit, but I'm very thankful to have not had to live there for an undetermined length of time. It is indeed a fascinating place - many people really do navigate the dating scene while following the halakhic rules, while many others invent rationalizations that even Bill Clinton would have been ashamed of. For details on the latter, check out this entry by Allison Kaplan Sommer. For examples of the former and latter, see this story by an old friend.