It passed by without any fanfare. I don't think anyone even noticed.
According to Geoff Huston's mathematical modeling we are now less than one year away from the final depletion of IANA's pool of free IPv4 netblocks.
The current estimate is that this will happen on 10th July 2011. What is going to happen you might ask...
An agreement was reached in the Internet community that as soon as the IANA has only 5 '/8' prefixes remaining in their pool they will all be handed out in one go. One prefix each to the 5 Regional Internet Registries (RIR). The registries are then responsible for distributing those addresses to users in their region.
Most RIRs have put in place policies that limit the maximum allocation size and rate of consumption of the final '/8'. This is intended to prevent a run-on-the-bank type situation and also try and ensure that small blocks of IPv4 addresses are available for critical systems such as DNS for a while.
The reality is that after July next year you are unlikely to be able to get an IPv4 allocation from your local RIR that will be big enough to build an ISP.
Are you ready for that?