That’s a very big block of scarce IPv4 addresses that have become available again. One block inside this /8, more specifically 18.145.0.0/16, was transferred to Amazon.
Net Range: 18.0.0.0 – 18.255.255.255
CIDR: 18.0.0.0/8
Name: NET18
Net Type: Allocated to ARIN
Organization: American Registry for Internet Numbers (ARIN)
Source: Whois-RWS
Update: more details of MIT’s IPv4 sale are now available.