The U.S. has hooker motels, of course, but they're anonymous-looking flea-infested dumps like you see along the highways running through industrial suburbs. Japan's love hotels have a slightly different aesthetic. Love hotels, at their most bizarre and intriguing, can out-creative the Vegas strip a hundredfold: there's a scale replica of the HMS QE II (the Sagamiko Elizabeth Sekitei) for the seafaring pervert, an Alcatraz-like "prison sex" hotel (Hotel The Rock) with a robotic warden, and, if you're into twee S&M, a hotel (the Adonis) with a Hello Kitty room. (These and many more here.)
This is old news, but since sex and tourism have more or less built the backbone of a successful internet, it's only natural that it's a popular story.
Related links (NSFW):
-Pantiespantiespanties' Travel Report: Osaka Love Hotels
-HotelChatter's Osaka Love Hotels: The Room Menu
-Gridskipper on The Ins and Outs of Love Hotels