https://qooah.com/2014/03/20/%e8%b7%9f%e9%80%b2-groupon%e5%9c%98%e8%b3%bc%e5%b0%8f%e7%b1%b3%e9%9b%bb%e6%ba%90%e6%87%b7%e7%96%91%e5%81%87%e8%b2%a8%e4%ba%8b%e4%bb%b6-%e9%a1%98%e9%80%80%e6%ac%be/