The most widely known is Azure, when they had to shuffle addresses around: http://www.internetsociety.org/deploy360/blog/2014/06/ipv4-exhaustion-gets-real-micr

The most widely known is Azure, when they had to shuffle addresses around: http://www.internetsociety.org/deploy360/blog/2014/06/ipv4-exhaustion-gets-real-microsoft-runs-out-of-u-s-addresses-for-azure-cloud-time-to-move-to-ipv6/ http://www.internetsociety.org/deploy360/blog/2014/06/ipv4-e... Google already started charging a nominal fee for idle IPv4 addresses: https://cloud.google.com/sql/ https://cloud.google.com/sql/, search for "Idle IPv4 address"