The idea of selling monthly subscriptions to a vast catalog of online music has met with only limited success. That isn’t stopping a new batch of entrepreneurs from trying to make it work, The New York Times reports. The latest and perhaps most surprising entrants to the field are the European entrepreneurs Niklas Zennstrom and Janus Friis. In 2001, they created and financed Kazaa, one of the original peer-to-peer file-sharing services that hurt the music industry. The two have created and financed a secretive start-up called Rdio, with offices in Los Angeles and San Francisco. Rdio and similar start-ups are reinventing a concept pioneered earlier this decade by Rhapsody, a service majority-owned by RealNetworks, and the tamed version of Napster, now owned by Best Buy. A few hundred thousand Rhapsody and Napster subscribers pay monthly fees of around $15 for the right to stream an unlimited number of songs, at any time, from their PCs and mobile devices. But with modest membership growth at best, neither service has managed to challenge iTunes, with its many millions of users — or enticed music lovers from pirating music. Moreover, Yahoo, AOL and MTV Networks have abandoned their own music subscription efforts.