I do not know about other sites on the list, but cember.net was not a clone. It was the sole player of business network in the time in Turkey. It gained real traction here and It's owners were out of ideas or out of interest of making money by running it. Then they have sold it for good money to Xing. If they haven't I believe they would burn out. And then cember.net "merged into" Xing and business networking in Turkey demolished.