Yesterday morning (26-April-2011), in US Bankruptcy Court for the District of Delaware, Judge Kevin Gross signed an order authorizing Nortel's sale of IPv4 addresses to Microsoft. This is an important moment for the Internet community, as it represents the beginning of a new market-based mechanism for the distribution of scarce IPv4 address resources. As the various Regional Internet Registry (RIR) organizations exhaust their supply, traditional "needs-based" distribution will become impossible. But an address market approach will enable organizations to continue growing their IPv4 networks (while transitioning to IPv6, as the economical choice).