The headquarters of what may be, on a per-capita basis, the busiest, most profitable site on the entire World Wide Web is on the 16th floor of a brand-new Vancouver building with panoramic views of the nearby Canadian Rockies.

It happens to be the apartment of 28-year-old Markus Frind, the owner and sole employee of PlentyOfFish.com, a free online dating site and a model for the next generation of Web entrepreneurship.

Lots...