The IMC paper “Census and Survey of the Visible Internet” was described in an article “Probe Sees Unused Internet” in the MIT Technology Review by Robert Lemos.
The article provides a nice summary of the issues, but it reaches a conclusion that is stronger supported by the study. The subhead of the article is “A survey shows that addresses are not running out as quickly as we’d thought”, and the article draws the conclusion: “the problem [of IPv4 address exhaustion] may not be as bad as many fear.”
The article’s conclusion, I think, overly simplifies matters—it is only true if the “better things we should be doing in managing the IPv4 address space” are free. The Internet Census we carried out supports the opportunity for better IPv4 address space management. But an open question is the cost of such management. Historically, with plentiful IPv4 addresses, IPv4 management costs have been small, but potential better IPv4 management will likely be much more costly. This cost of ongoing IPv4 management needs to be weighed against the costs of one-time conversion cost to IPv6 coupled followed lower IPv6 management costs.
To me, one exciting conclusion from the Internet Census we carried out is that we now have data that allows us to start evaluating these trade-offs. The answer may be more careful IPv4 gets us a few years, or that the cost of more careful IPv4 makes IPv6 an obvious choice. In either case, resolving this transition is important for the Internet community.